Methods for making lignocellulose containing composite products

ABSTRACT

Methods for making composite products are provided. In at least one specific embodiment, the method can include combining a plurality of lignocellulose substrates and one or more free radical precursors to produce a mixture of the lignocellulose substrates and the one or more free radical precursors. The method can also include maintaining the mixture at a temperature less than 60° C. for at least 10 minutes while retaining at least 11 wt % of the one or more free radical precursors charged to the mixture. The method can then include heating the mixture comprising at least 11 wt % of the one or more free radical precursors charged to the mixture to a temperature of at least 60° C. to about 300° C. to produce a composite product. The composite product can have a density less than 1 g/cm 3  and an internal bond strength of at least 0.35 MPa.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to U.S. Provisional Patent Applicationhaving Ser. No. 61/708,395, filed Oct. 1, 2012, which is incorporated byreference herein.

BACKGROUND

1. Field

Embodiments described herein generally relate to methods for makinglignocellulose containing composite products. Embodiments describedherein also generally relate to catalysts for use in makinglignocellulose containing composite products.

2. Description of the Related Art

The production of lignocellulose composite products requires an adhesiveor binder to bond the discrete, particulates, fibers, veneers, or othersubstrates to one another. Typical lignocellulose composite productsinclude particleboard, fiberboard, plywood, and the like. Conventionalbinders used in the production of these products frequently containformaldehyde based resins such as urea-formaldehyde (UF),melamine-formaldehyde (MF), melamine-urea-formaldehyde (MUF), andphenol-formaldehyde (PF) binders. While formaldehyde based resinsproduce finished products having desirable properties, such as strength,these binders also release formaldehyde into the environment during theproduction of the binder, curing of the binder/composite product, aswell as, from the final product made using the binder.

Various techniques have been used to reduce the amount of formaldehydereleased from formaldehyde based resins. For example, the addition offormaldehyde scavengers to the resin and/or various modifications to theparticular synthesis steps used to make the formaldehyde based resin,such as the addition of urea as a reactant late in the binder synthesis,are often used in an attempt to reduce formaldehyde emission. Theseattempts to reduce formaldehyde emission, however, are accompanied withundesirable effects such as longer cure time, reduced resin shelf-life,reduced product strength, reduced tolerance for processing variations,and/or inferior moisture resistance.

There is a need, therefore, for improved methods for makinglignocellulose containing composite products having reduced or noformaldehyde emission.

SUMMARY

Methods for making composite products are provided. In at least onespecific embodiment, the method can include combining a plurality oflignocellulose substrates and one or more free radical precursors toproduce a mixture of the lignocellulose substrates and the one or morefree radical precursors. The method can also include maintaining themixture at a temperature less than 60° C. for at least 10 minutes whileretaining at least 11 wt % of the one or more free radical precursorscharged to the mixture. The method can then include heating the mixturecomprising at least 11 wt % of the one or more free radical precursorscharged to the mixture to a temperature of at least 60° C. to about 300°C. to produce a composite product. The composite product can have adensity less than 1 g/cm³ and an internal bond strength of at least 0.35MPa.

In at least one specific embodiment, the method for making a compositeproduct can include combining a plurality of lignocellulose substrates,one or more free radical precursors, and one or more compoundscomprising at least two hydrogen atoms that are abstractable in thepresence of hydroxyl radicals to produce a mixture. The method can alsoinclude heating the mixture comprising at least 11 wt % of the one ormore free radical precursors charged to the mixture to a temperature ofat least 60° C. to about 300° C. to produce a composite product.

In at least one specific embodiment, a composite product can include anat least partially cured composition having a density less than 1 g/cm³and an internal bond strength of at least 0.35 MPa. The composition,prior to curing, can include a plurality of lignocellulose substrates,one or more free radical precursors, and one or more compoundscomprising at least two hydrogen atoms that are abstractable in thepresence of hydroxyl radicals.

DETAILED DESCRIPTION

The plurality of lignocellulose substrates and the one or more freeradical precursors can be mixed, blended, stirred, contacted, orotherwise combined with one another to produce the mixture. One or morecompounds comprising at least two hydrogen atoms that are abstractablein the presence of hydroxyl radicals can optionally be combined with thelignocellulose substrates and the free radical precursor and, ifpresent, the catalyst to produce the mixture. The mixture can also bereferred to as a “furnish,” “blended furnish,” “resinated mixture,” or“resinated furnish.” The mixture can be heated to produce thelignocellulose containing composite product or “composite product.” Forexample, the mixture can be heated to a temperature from a low of 60°C., about 90° C., about 120° C., about 150° C., or about 160° C. to ahigh of about 170° C., about 200° C., about 230° C., about 260° C., orabout 300° C. to produce the composite product. In another example, themixture can be heated to a temperature of at least 60° C., at least 70°C., at least 80° C., at least 90° C., at least 100° C., at least 110°C., at least 120° C., at least 130° C., or at least 140° C. to about150° C., about 155° C., about 160° C., about 165° C., about 170° C.,about 180° C., about 200° C., about 225° C., about 250° C., about 275°C., or about 300° C. In another example, the mixture can be heated to atemperature of about 140° C. to about 200° C., about 155° C. to about175° C., about 160° C. to about 210° C., about 160° C. to about 175° C.,or about 145° C. to about 225° C.

In one or more embodiments, the mixture can be heated in air. In one ormore embodiments, the mixture can be heated in an inert atmosphere orsubstantially an inert atmosphere such as nitrogen. If the mixture isheated in a substantially inert atmosphere the amount of oxygen can beless than about 5 mol %, less than about 3 mol %, less than about 1 mol%, less than about 0.5 mol %, or less than about 0.1 mol % oxygen.Suitable inert gases can include, but are not limited to, nitrogen,argon, or a mixture thereof.

Heating the mixture can cause or promote the at least partial curing ofthe mixture to produce the composite product. As used herein, the terms“curing,” “cured,” “at least partially curing,” “at least partiallycured,” and similar terms are intended to refer to the structural and/ormorphological change that occurs in the mixture, such as by covalentchemical reaction (crosslinking), ionic interaction or clustering, phasetransformation or inversion, and/or hydrogen bonding when the issubjected to conditions sufficient, e.g., sufficiently heated, to causethe properties of a flexible, porous substrate, such as a nonwoven mator blanket of lignocellulose substrates and/or a rigid or semi-rigidsubstrate, such as a wood or other lignocellulose containing board orsheet, to which an effective amount of the free radical precursor and,optionally, the polyphenolic compound has been applied, to be altered.

When the mixture is heated, the mixture can contain at least a portionof the free radical precursor initially added to and present in themixture. Said another way, at least a portion of the free radicalprecursor can remain unreacted or otherwise in the same form as whencombined with the additional components of the mixture at least untilthe mixture is heated to an elevated temperature such as about 60° C. ormore. For example, if the free radical precursor includes one or moreoxidants, e.g., hydrogen peroxide (H₂O₂), at least a portion of theoxidant in the form of hydrogen peroxide (H₂O₂) can be present whenheating of the mixture is initiated or started. In one or moreembodiments, the mixture can contain at least 11 wt %, at least 13 wt %,at least 15 wt %, at least 20 wt %, at least 25 wt %, at least 30 wt %,at least 35 wt %, at least 40 wt %, at least 45 wt %, at least 50 wt %,at least 55 wt %, at least 60 wt %, at least 65 wt %, or at least 70 wt% of the total or initial amount of free radical precursor initiallypresent in the mixture, i.e., the amount of the free radical precursorcombined with the plurality of lignocellulose substrates to produce themixture, when the mixture is heated to a temperature of at least 60° C.In another example, the amount of the free radical precursor presentwhen the mixture is heated to a temperature of at least 60° C. can be atleast 11 wt %, at least 13%, at least 15 wt %, at least 20 wt %, atleast 25 wt %, at least 30 wt %, at least 35 wt %, at least 40 wt %, atleast 45 wt %, at least 50 wt %, at least 55 wt %, at least 60 wt %, atleast 65 wt %, or at least 70 wt % of the one or more free radicalprecursors combined with the plurality of lignocellulose substrates. Instill another example, the amount of the free radical precursor presentwhen the mixture is heated to a temperature of at least 60° C., at least65° C., or at least 70° C. can be at least 11 wt %, at least 13%, atleast 15 wt %, at least 20 wt %, at least 25 wt %, at least 30 wt %, atleast 35 wt %, at least 40 wt %, at least 45 wt %, at least 50 wt %, atleast 55 wt %, at least 60 wt %, at least 65 wt %, or at least 70 wt %of the one or more free radical precursors combined with the pluralityof lignocellulose substrates. In another example, the mixture cancontain from about 11% to about 95%, about 15% to about 85%, about 20%to about 90%, about 30% to about 80%, about 11% to about 100%, about 35%to about 75%, about 40% to about 70%, about 50% to about 70%, about 60%to about 80%, about 65% to about 85%, or about 30% to about 95% of thetotal amount of free radical precursor initially present in the mixturewhen the mixture is heated. In at least one specific example, if themixture can include about 5 wt % free radical precursor, based on thedry weight of the lignocellulose substrates when the mixture isinitially formed and when the mixture is heated to a temperature of 60°C. or more at least 11% of the free radical precursor can be present inthe mixture. Said another way, if the mixture contains about 5 wt % ofthe one or more free radical precursors, based on the dry weight of thelignocellulose substrates, upon preparation or formation of the mixture,when heating the mixture is initiated or started, the mixture can have afree radical precursor concentration of at least 11% of the initial 5 wt% or 0.55 wt %, based on the dry weight of the lignocellulosesubstrates.

In one or more embodiments, the amount of the one or more free radicalprecursors present when the mixture is heated, e.g., to a temperature ofabout 60° C. to about 300° C., can be at least 0.5 wt %, at least 0.7 wt%, at least 1 wt %, at least 1.2 wt %, at least 1.5 wt %, at least 1.7wt %, at least 2 wt %, at least 2.2 wt %, at least 2.5 wt %, at least2.7 wt %, at least 3 wt %, at least 3.2 wt %, at least 3.5 wt %, atleast 3.7 wt %, at least 4 wt %, at least 4.2 wt %, at least 4.5 wt %,at least 4.7 wt %, or at least 5 wt %, based on the dry weight of theplurality of lignocellulose substrates. For example, the amount of theone or more free radical precursors present when the mixture is heatedcan be from a low of about 1 wt %, about 1.5 wt %, about 1.6 wt %, about1.8 wt %, or about 2.1 wt % to high of about 5 wt %, about 7 wt %, about10 wt %, about 15 wt %, about 20 wt % or more, based on the dry weightof the plurality of lignocellulose substrates. In another example, theamount of the one or more free radical precursors present when themixture is heated can be from about 1 wt % to about 10 wt %, about 1.5wt % to about 7 wt %, about 2 wt % to about 6 wt %, about 2.5 wt % toabout 8 wt %, about 3 wt % to about 5.5 wt %, about 4 wt % to about 6.5wt %, about 2.2 wt % to about 11 wt %, or about 2.3 wt % to about 6.3 wt%, based on the dry weight of the plurality of lignocellulosesubstrates.

The mixture can be heated as soon as the mixture is formed. The mixturecan be kept, held, or otherwise maintained at a temperature less thanabout 60° C. for a period of time prior to heating the mixture to atemperature of at least 60° C. At least one way an exothermic reactionbetween the components of the mixture can be substantially andsignificantly slowed and/or prevented such that the mixture does notsignificantly increase in temperature until the mixture is intentionallyheated can be to select an appropriate free radial precursor or mixtureof free radical precursors. In other words, the temperature of themixture, without external heat directed to the mixture, can remain freefrom or substantially free from the development of an exotherm byselectively selecting an appropriate free radical precursor(s). Theparticular temperature of the mixture during the time period beforeheating can depend, at least in part, on the ambient or environmentaltemperature where the mixture is located. In one or more embodiments,the mixture can be maintained at a temperature of less than 60° C.without any intentional removal of heat therefrom. In one or moreembodiments, the mixture can be maintained at a temperature of less than60° C. with removal of heat therefrom, e.g., the mixture can be locatedwithin a refrigeration device and/or a cooled fluid such as chilled aircan be directed toward and/or passed through the mixture. In one or moreembodiments, the mixture can be maintained at a temperature of less than60° C. by controlling or adjusting a water concentration of the mixture.For example, increasing the water concentration of the mixture canreduce, inhibit, or prevent the mixture from undergoing an exothermicreaction.

Prior to heating the mixture to a temperature of at least 60° C., themixture can be maintained at a temperature less than 60° C., less than55° C., less than 50° C., less than 45° C., less than 40° C., less than35° C., or less than 30° C. for at least 10 minutes, at least 13minutes, at least 15 minutes, at least 17 minutes, at least 20 minutes,at least 23 minutes, at least 25 minutes, at least 27 minutes, at least30 minutes, at least 33 minutes, at least 35 minutes, at least 37minutes, at least 40 minutes, at least 43 minutes, at least 45 minutes,at least 47 minutes, at least 50 minutes, at least 53 minutes, at least55 minutes, at least 57 minutes, or at least 60 minutes. For example,the mixture can be maintained at a temperature less than 60° C. for atleast 10 minutes to about 30 minutes, at least about 15 minutes to about35 minutes, at least about 20 minutes to about 40 minutes, at leastabout 18 minutes to about 45 minutes, or at least about 15 minutes toabout 40 minutes prior to heating the mixture to a temperature of atleast 60° C. In another example, the mixture can be maintained at atemperature less than 60° C. for at least 10 minutes, about 30 minutes,about 45 minutes, about 1 hour, about 2 hours, about 3 hours, about 5hours, about 12 hours, about 18 hours, about 24 hours, or about 30 hoursprior to heating the mixture to a temperature of at least 60° C.

Prior to heating the mixture to a temperature of at least 60° C., theamount of energy generated from the mixture due to exothermicreaction(s) can be less than about 35 cal/g of the mixture, less thanabout 30 cal/g of the mixture, less than about 25 cal/g of the mixture,less than about 23 cal/g of the mixture, less than about 20 cal/g of themixture, less than about 18 cal/g of the mixture, less than about 16cal/g of the mixture, less than about 15 cal/g of the mixture, less thanabout 14 cal/g of the mixture, or less than about 13.8 cal/g of themixture. For example, prior to heating the mixture to a temperature ofat least 60° C., the amount of energy generated from the mixture due toexothermic reaction(s) can be less than 14 cal/g, less than 13.5 cal/g,less than 13 cal/g, less than 12.5 cal/g, less than 12 cal/g, less than11.5 cal/g, less than 11 cal/g, less than 10.5 cal/g, less than 10cal/g, less than 9.5 cal/g, less than 9 cal/g, less than 8.5 cal/g, lessthan 8 cal/g, less than 7.5 cal/g, less than 7 cal/g, less than 6.5cal/g, less than 6 cal/g, less than 5.5 cal/g, less than 5 cal/g, lessthan 4.5 cal/g, less than 4 cal/g, less than 3.5 cal/g, less than 3cal/g, less than 2.5 cal/g. less than 2 cal/g, less than 1.5 cal/g, lessthan 1 cal/g, or less than 0.5 cal/g of the mixture.

Composite products in the shape or form of a panel, sheet, board, or thelike can be in the form of a rectangular prism that includes six outersurfaces, i.e., three pairs of oppositely facing surfaces. The firstpair of oppositely facing surfaces of the composite product can includea first or “top” surface and an opposing second or “bottom” surface. Thesecond and third pairs of oppositely facing surfaces of the compositeproduct can be referred to as the “side surfaces” that have a surfacearea less than the surface area of the first and second surfaces. Assuch, composite products in the shape or form of a panel, sheet, board,or the like can have an average thickness, where the average thicknessis the length or distance between the first and second surfaces.

If the composite product is in the form of a panel, sheet, board, or thelike, the amount or length of time the mixture can be heated can rangefrom a low of about 5 seconds per millimeter (s/mm), about 10 s/mm,about 12 s/mm, or about 15 s/mm to a high of about 17 s/mm, about 19s/mm, about 21 s/mm, about 23 s/mm, about 25 s/mm, about 27 s/mm, about30 s/mm, about 35 s/mm, about 40 s/mm, about 50 s/mm, or about 60 s/mm,where the length refers to the average thickness of the compositeproduct, and with suitable ranges including the combination of any twovalues. For example, the mixture can be heated for a time of about 7s/mm to about 27 s/mm, about 9 s/mm to about 24 s/mm, about 11 s/mm toabout 22 s/mm, about 8 s/mm to about 20 s/mm, about 14 s/mm to about 18s/mm, about 6 s/mm to about 14 s/mm, about 10 s/mm to about 18 s/mm, orabout 10 s/mm to about 16 s/mm, where the length refers to the averagethickness of the composite product. In another example, the mixture canbe heated for a time less than 22 s/mm, less than 20 s/mm, less than 18s/mm, less than 17 s/mm, less than 16 s/mm, less than 15 s/mm, less than14 s/mm, less than 13 s/mm, or less than 12 s/mm, where the lengthrefers to the average thickness of the composite product. In onespecific example, a composite product in the form of a panel, sheet,board, or the like and having an average thickness of about 15 mm andsubjected to a total heating time of about 4 minutes would correspond toheating the mixture for about 16 s/mm. In at least one specific example,the mixture can be heated to a temperature of about 160° C. to about170° C. for a time of 13 s/mm to about 19 s/mm.

Pressure can optionally be applied to the mixture before, during, and/orafter the mixture is heated to produce the composite product. Forexample, if the desired composite product shape or structure is a panel,sheet, board, or the like, an amount of the mixture sufficient toproduce a composite product of the desired size, can be transported,directed, placed, introduced, disposed, or otherwise located within apress capable of pressing the mixture before the mixture is heatedand/or when the mixture is heated. The press can be an open press or aclosed press. In at least one specific embodiment, an open press can beused to press the mixture when the mixture is heated, e.g., to atemperature of about 100° C. to about 250° C. In another example, themixture can be extruded through a die (extrusion process) and heated toproduce the composite product. The mixture can be pressed under apressure from a low of about 0.5 MPa, about 1 MPa, about 3 MPa, or about5 MPa to a high of about 7 MPa, about 9 MPa, or about 11 MPa.

Illustrative open presses can be as discussed and described in U.S. Pat.Nos. 4,017,248; 5,337,655; 5,611,269; 5,950,532; 6,098,532; and6,782,810. Suitable, commercially available, open presses can include,but are not limited to, the CONTIROLL® press available from Siempelkampand the CPS press available from Dieffenbacher.

The pH of the mixture can be acidic, neutral, or basic. For example, thepH of the mixture can be from a low of about 1, about 2, or about 3 to ahigh of about 4, about 5, about 6, about 7, or about 8, with suitableranges including the combination of any two values. In another example,the pH of the mixture can be from about 1 to about 6, about 1.5 to about5.5, about 2.5 to about 4.5, about 2 to about 3.5, or about 2.5 to about3.5. The pH of the mixture can be adjusted to any desired pH bycombining one or more base compounds, one or more acid compounds, or acombination of one or more base compounds and one or more acid compoundstherewith.

Illustrative base compounds that can be used to adjust the pH of themixture can include, but are not limited to, hydroxides, carbonates,ammonia, amines, any combination thereof, or any mixture thereof.Illustrative hydroxides can include, but are not limited to, sodiumhydroxide, potassium hydroxide, ammonium hydroxide (e.g., aqueousammonia), lithium hydroxide, and cesium hydroxide. Illustrativecarbonates can include, but are not limited to, sodium carbonate, sodiumbicarbonate, potassium carbonate, and ammonium carbonate. Illustrativeamines can include, but are not limited to, trimethylamine,triethylamine, triethanolamine, diisopropylethylamine (Hunig's base),pyridine, 4-dimethylaminopyridine (DMAP), and1,4-diazabicyclo[2.2.2]octane (DABCO).

Illustrative acid compounds that can be used to adjust the pH of themixture can include, but are not limited to, one or more mineral acids,one or more organic acids, one or more acid salts, any combinationthereof, or any mixture thereof. Illustrative mineral acids can include,but are not limited to, hydrochloric acid, nitric acid, phosphoric acid,sulfuric acid, any combination thereof, or any mixture thereof.Illustrative organic acids can include, but are not limited to, aceticacid, formic acid, citric acid, oxalic acid, uric acid, lactic acid, anycombination thereof, or any mixture thereof. Illustrative acid salts caninclude, but are not limited to, ammonium sulfate, sodium bisulfate,sodium metabisulfite, any combination thereof, or any mixture thereof.

The mixture can include one or more liquid mediums. The one or moreliquid mediums can be present in any one or more of the lignocellulosesubstrates, the free radical precursor, and/or the optional compoundcomprising at least two hydrogen atoms that are abstractable in thepresence of hydroxyl radicals. The liquid medium can be or include, butis not limited to, water, alcohols, glycols, acetonitrile, dimethylsulfoxide, N,N-dimethylformamide, N-methylpyrrolidone, any combinationthereof, or any mixture thereof. Suitable alcohols can include, but arenot limited to, methanol, ethanol, propanol, isopropanol, butanol, anycombination thereof, or any mixture thereof. Suitable glycols caninclude, but are not limited to, ethylene glycol, propylene glycol, or acombination thereof. As used herein, the terms “aqueous medium” and“aqueous liquid” can be or include water and/or mixtures composed ofwater and/or other water-miscible solvents. Illustrative water-misciblesolvents can include, but are not limited to, alcohols, ethers, amines,other polar aprotic solvents, and the like. In at least one example, theliquid medium can be water and the catalyst, the oxidant, and/or thepolyphenolic compound can be combined with water.

The mixture can have a liquid, e.g., water, content from a low of about1 wt %, about 3 wt %, about 5 wt %, or about 10 wt % to high of about 12wt %, about 14 wt %, about 16 wt %, about 18 wt %, about 20 wt %, about22 wt %, or about 24 wt %, based on the total weight of the mixture,with suitable ranges including the combination of any two values. Forexample, when the mixture contains water as the liquid, the mixture canhave a moisture content of about 10 wt % to about 25 wt %, about 12 wt %to about 20 wt %, about 11 wt % to about 19 wt %, about 13 wt % to about18 wt %, about 15 wt % to about 18 wt %, about 12 wt % to about 17 wt %,or about 14 wt % to about 17 wt %, based on the total weight of themixture.

The components of the mixture can be combined simultaneously or in anyorder or sequence with respect to one another. For example, the freeradical precursor and, if present, the one or more compounds having atleast two hydrogen atoms that are abstractable in the presence ofhydroxyl radicals can be combined with the lignocellulose substratessimultaneously. In another example, the free radical precursor can becombined with the lignocellulose substrates to produce a first mixtureand then the optional compound having at least two hydrogen atoms thatare abstractable in the presence of hydroxyl radicals can be combinedwith the first mixture to produce the mixture. In another example, thecompound having at least two hydrogen atoms that are abstractable in thepresence of hydroxyl radicals can be combined with the lignocellulosesubstrates to produce a first or partial mixture, and then the freeradical precursor can be combined with the first or partial mixture toproduce the mixture.

If the free radical precursor includes two or more components, e.g., acatalyst and an oxidant, the components of the free radical precursorcan be combined with the lignocellulose substrates and the optionalcompound having at least two hydrogen atoms that are abstractable in thepresence of hydroxyl radicals in any order or sequence. For example, ifthe free radical precursor includes a catalyst and an oxidant, thecatalyst can be combined with the lignocellulose substrates to produce afirst partial mixture and the oxidant can be combined with the firstpartial mixture to produce the mixture or vice versa. In anotherexample, the catalyst and the compound having at least two hydrogenatoms that are abstractable in the presence of hydroxyl radicals can becombined with one another to produce a first partial mixture, the firstpartial mixture can be combined with the lignocellulose substrates toproduce a second partial mixture, and the oxidant can be combined withthe second partial mixture to produce the mixture. In still anotherexample, the oxidant and the compound having at least two hydrogen atomsthat are abstractable in the presence of hydroxyl radicals can becombined with one another to produce a first partial mixture, the firstpartial mixture can be combined with the lignocellulose substrates toproduce a second partial mixture, and the catalyst can be combined withthe second partial mixture to produce the mixture. In another example,the oxidant and the catalyst can be combined with one another to producea first partial mixture, the first partial mixture can be combined withthe lignocellulose substrates to produce a second partial mixture, andthe compound having at least two hydrogen atoms that are abstractable inthe presence of hydroxyl radicals can be combined with the secondpartial mixture to produce the mixture.

The components of the mixture can be introduced or otherwise contactedwith one another via any suitable delivery method. For example, thelignocellulose substrates can be in a vessel or other container and thefree radical precursor, and, if present, the compound having at leasttwo hydrogen atoms that are extractable in the presence of hydroxylradicals can be sprayed or otherwise directed onto the lignocellulosesubstrates to produce the mixture. In another example, the free radicalprecursor, and, if present, the compound having at least two hydrogenatoms that are extractable in the presence of hydroxyl radicals can bepoured or brushed onto the lignocellulose substrates. In anotherexample, the lignocellulose substrates can be directed, transported,introduced, or otherwise conveyed into a vessel already containing anyone or more of the other components of the mixture. Said another way,the lignocellulose substrates can be dipped, soaked, or otherwisecontacted with the free radical precursor and, optionally, the compoundhaving at least two hydrogen atoms that are extractable in the presenceof hydroxyl radicals.

As used herein, the term free radical precursor refers to any compoundor mixture of compounds that can generate radicals when subjected topredetermined conditions. For example, the free radical precursor can bea compound or mixture of compounds that can generate radicals whenheated to a predetermined temperature. In another example, the freeradical precursor can be a compound or mixture of compounds that cangenerate radicals when hydrogen peroxide (oxidant) is subjected toreaction with one or more transition metals (catalyst).

The amount of free radical precursor present in the mixture can depend,at least in part, on the particular composition of the free radicalprecursor, lignocellulose substrates, and/or, if present, the compoundhaving at least two hydrogen atoms that are abstractable in the presenceof hydroxyl radicals and, thus, can widely vary. For example, the amountof radical precursor in the mixture can be from about 1 wt % to about200 wt %, based on the dry weight of the lignocellulose substrates. Inanother example, the amount of radical precursor in the mixture can befrom a low of about 1 wt %, about 5 wt %, about 10 wt %, or about 20 wt% to a high of about 80 wt %, about 100 wt %, about 120 wt %, or about150 wt %, based on the dry weight of the lignocellulose substrates, withsuitable ranges including the combination of any two values. In anotherexample, the radical precursor can be present in the mixture in anamount from about 0.1 wt % to about 30 wt %, about 1 wt % to about 20 wt%, about 5 wt % to about 50 wt %, about 10 wt % to about 70 wt %, about0.5 wt % to about 25 wt %, about 3 wt % to about 6 wt %, or about 2 wt %to about 8 wt %, based on the dry weight of the lignocellulosesubstrates. In still another example, the radical precursor can bepresent in the mixture in amount of about 0.1 wt % to about 10 wt %,about 1 wt % to about 12 wt %, about 2 wt % to about 9 wt %, about 3 wt% to about 9 wt %, about 5 wt % to about 15 wt %, about 4 wt % to about6 wt %, about 8 wt % to about 20 wt %, or about 2 wt % to about 10 wt %,based on the dry weight of the lignocellulose substrates.

In one or more embodiments, the amount of the free radical precursor inthe mixture can be about 3 wt %, about 4 wt %, about 5 wt %, about 6 wt%, about 7 wt %, about 8 wt %, about 9 wt %, or about 10 wt % and priorto heating the mixture to a temperature of at least 60° C., the amountof energy generated from the mixture due to any exothermic reaction(s)can be less than about 75 cal/g of the mixture, less than about 69 cal/gof the mixture, less than about 62 cal/g of the mixture, less than about55 cal/g of the mixture, less than about 48 cal/g of the mixture, lessthan about 42 cal/g of the mixture, less than about 34 cal/g of themixture, less than about 27 cal/g of the mixture, less than about 20cal/g of the mixture, or less than about 13 cal/g of the mixture. Forexample, the amount of the free radical precursor in the mixture can beabout 3 wt % and prior to heating the mixture to a temperature of atleast 60° C., the amount of energy generated from the mixture due toexothermic reaction(s) can be less than about 21 cal/g of the mixture,less than about 20 cal/g of the mixture, less than about 18 cal/g of themixture, less than about 16 cal/g of the mixture, less than about 14cal/g of the mixture, less than about 12 cal/g of the mixture, less thanabout 10 cal/g of the mixture, less than about 8 cal/g of the mixture,less than about 6 cal/g of the mixture, or less than about 4 cal/g ofthe mixture. In another example, the amount of the free radicalprecursor in the mixture can be about 4 wt % and prior to heating themixture to a temperature of at least 60° C., the amount of energygenerated from the mixture due to exothermic reaction(s) can be lessthan about 28 cal/g of the mixture, less than about 26 cal/g of themixture, less than about 24 cal/g of the mixture, less than about 22cal/g of the mixture, less than about 20 cal/g of the mixture, less thanabout 18 cal/g of the mixture, less than about 16 cal/g of the mixture,less than about 14 cal/g of the mixture, less than about 12 cal/g of themixture, or less than about 10 cal/g of the mixture. In another example,the amount of the free radical precursor in the mixture can be about 5wt % and prior to heating the mixture to a temperature of at least 60°C., the amount of energy generated from the mixture due to exothermicreaction(s) can be less than about 35 cal/g of the mixture, less thanabout 33 cal/g of the mixture, less than about 31 cal/g of the mixture,less than about 29 cal/g of the mixture, less than about 27 cal/g of themixture, less than about 25 cal/g of the mixture, less than about 23cal/g of the mixture, less than about 21 cal/g of the mixture, less thanabout 19 cal/g of the mixture, or less than about 17 cal/g of themixture. In another example, the amount of the free radical precursor inthe mixture can be about 6 wt % and prior to heating the mixture to atemperature of at least 60° C., the amount of energy generated from themixture due to exothermic reaction(s) can be less than about 42 cal/g ofthe mixture, less than about 40 cal/g of the mixture, less than about 38cal/g of the mixture, less than about 36 cal/g of the mixture, less thanabout 34 cal/g of the mixture, less than about 32 cal/g of the mixture,less than about 30 cal/g of the mixture, less than about 28 cal/g of themixture, less than about 26 cal/g of the mixture, or less than about 24cal/g of the mixture. In another example, the amount of the free radicalprecursor in the mixture can be about 7 wt % and prior to heating themixture to a temperature of at least 60° C., the amount of energygenerated from the mixture due to exothermic reaction(s) can be lessthan about 49 cal/g of the mixture, less than about 45 cal/g of themixture, less than about 40 cal/g of the mixture, less than about 35cal/g of the mixture, less than about 30 cal/g of the mixture, less thanabout 25 cal/g of the mixture, less than about 20 cal/g of the mixture,less than about 15 cal/g of the mixture, less than about 10 cal/g of themixture, or less than about 8 cal/g of the mixture.

Illustrative free radical precursors can include, but are not limitedto, one or more azo compounds, one or more oxidants, a combination ormixture of one or more catalysts and one or more oxidants, or anymixture or combination thereof. Illustrative azo compounds can berepresented by the general formula R—N═N—R′, where R and R′ canindependently be substituted aryl or substituted alkyl. The term “aryl”refers to an aromatic substituent containing a single aromatic ring ormultiple aromatic rings that are fused together, linked covalently, orlinked to a common group such as a methylene or ethylene moiety. Morespecific aryl groups contain one aromatic ring or two or three fused orlinked aromatic rings, e.g., phenyl, naphthyl, biphenyl, anthracenyl,phenanthrenyl, and the like. In one or more embodiments, arylsubstituents can have from 1 to about 20 carbon atoms. The alkyl caninclude branched or unbranched alkyls having from 1 to about 15 carbonatoms or more preferably from 1 to about 8 carbon atoms. Illustrativealkyls can include, but are not limited to, methyl, ethyl, n-propyl,isopropyl, isobutyl, n-butyl, sec butyl, t-butyl, n-pentyl, n-hexyl, andethylhexyl. Suitable azo compounds can include, but are not limited to,azobisisobutyronitrile (AIBN).

The catalyst, if present in the free radical precursor, can also bereferred to as an initiator, a promoter, a reducer, and/or anaccelerator. Suitable catalysts can be or include, but are not limitedto, metal ions, tertiary amines, polymeric tertiary amines, polyamines,phosphates, bisulfites, metabisulfites, tetraacetylethylenediamine,cyanamides, ultraviolet light, any combination thereof, or any mixturethereof. Any catalyst or combination of catalysts can be combined withthe lignocellulose substrates and the oxidant to produce the mixture. Inaddition to or in lieu of contacting the lignocellulose substrates withan oxidant and/or catalyst, ultrasonic waves, photo-Fenton and/orelectro-Fenton reactions (in situ generation of hydroxyl radicals byradiation or electric currents) can be used.

Suitable metal can include one or more Group 3 to Group 12 metal atoms.As used herein, all reference to the Periodic Table of the Elements andgroups thereof is to the NEW NOTATION published in HAWLEY'S CONDENSEDCHEMICAL DICTIONARY, Thirteenth Edition, John Wiley & Sons, Inc., (1997)(reproduced there with permission from IUPAC) unless otherwise noted.Illustrative transition metals can include, but are not limited to,metal ions of iron, copper, manganese, tungsten, molybdenum, cobalt,titanium, or any combination or mixture thereof. The metal can be in theform of an oxide. The metal can be in the form of a salt or complex. Forexample, the metal can be bound to one or more complexing agents orcompounds. Illustrative complexing agents or complexing compounds caninclude, but are not limited to, cyanide (CN), sulfate (SO₄ ²⁻),ethylenediaminetetraacetic acid (EDTA), ethylenediamine-N,N′-disuccinicacid (EDDS), ethyleneglycol bis(2-aminoethyl ter)-N,N,N′,N′-tetraaceticacid (EGTA), diethylenetriaminepentaacetic acid (DTPA),trans-1,2-diaminocyclohexane tetraacetic acid (CDTA), iminodisuccinate(IDS), nitrilotracetic acid (NTA), or any combination or mixturethereof. Other complexing compounds can include phosphates, orcomplexing agents based on phosphonic acid, oxalic acid, ascorbic acid,nitrilo acetate, gallic acid, fulvic acid, or polyoxomethalates.

In one or more embodiments, the catalyst can include Fe²⁺ or Fe³⁺ ionssuch as iron(II) sulfate, iron(II) oxide, iron(III) sulfate, iron(III)oxide. Other iron ion containing catalysts can include, but are notlimited to, [Fe(CN)₆]³⁻, ferrocyanide [Fe(CN)₆]⁴⁻, and/or [Fe(CN)₅N0]²⁻.For example, the catalyst can be or include, but is not limited to,potassium ferricyanide (K₃[Fe(CN)₆]), potassium ferrocyanide(K₄[Fe(CN)₆]), ammonium hexacyanoferrate(II) hydrate((NH₄)₄[Fe(CN)₆].xH₂O), ammonium iron(III) hexacyanoferrate(II) hydrate,sodium ferrocyanide decahydrate (Na₄[Fe(CN)₆].10H₂O), sodiumnitroprusside dihydrate (Na₂[Fe(CN)₅NO].2H₂O). Other suitable catalystthat contain iron can include, but are not limited to, Fe[EDTA],Fe[EDDS], Fe[DTPA], Fe[EGTA], Fe[CDTA], Fe[IDS], or any mixture thereof.In at least one specific embodiment, the catalyst preferably includesferricyanide, e.g., potassium ferricyanide, a complex of iron andethylenediaminetetraacetic acid (EDTA), a complex of iron and(S,S)-ethylenediamine-N,N′-disuccinic acid ((S,S)-EDDS), a complex ofiron and (R,R)-ethylenediamine-N,N′-disuccinic acid ((R,R)-EDDS), acomplex of iron and (R,S)-ethylenediamine-N,N′-disuccinic acid((R,S)-EDDS), a complex of iron and diethylenetriaminepentaacetic acid(DTPA), a complex of iron and trans-1,2-diaminocyclohexane tetraaceticacid (DCTA), a complex of iron and iminodisuccinate (IDS), or anymixture thereof.

Tertiary amines can be represented by the general formula NR₁R₂R₃, whereeach R₁, R₂, and R₃ is independently selected from alkyls, cycloalkyls,heterocycloalkyls, aryls, heteroaryls, and substituted aryls. The alkylcan include branched or unbranched alkyls having from 1 to about 15carbon atoms or more preferably from 1 to about 8 carbon atoms.Illustrative alkyls can include, but are not limited to, methyl, ethyl,n-propyl, isopropyl, n-butyl, sec butyl, t-butyl, n-pentyl, n-hexyl, andethylhexyl. The cycloalkyls can include from 3 to 7 carbon atoms.Illustrative cycloalkyls can include, but are not limited to,cyclopentyl, substituted cyclopentyl, cyclohexyl, and substitutedcyclohexyl. The term “aryl” refers to an aromatic substituent containinga single aromatic ring or multiple aromatic rings that are fusedtogether, linked covalently, or linked to a common group such as amethylene or ethylene moiety. More specific aryl groups contain onearomatic ring or two or three fused or linked aromatic rings, e.g.,phenyl, naphthyl, biphenyl, anthracenyl, phenanthrenyl, and the like.The aryl substituents can include from 1 to about 20 carbon atoms. Theterm “heteroatom-containing,” as in a “heteroatom-containing cycloalkylgroup,” refers to a molecule or molecular fragment in which one or morecarbon atoms is replaced with an atom other than carbon, e.g., nitrogen,oxygen, sulfur, phosphorus, boron, or silicon. Similarly, the term“heteroaryl” refers to an aryl substituent that isheteroatom-containing. The term “substituted,” as in “substitutedaryls,” refers to a molecule or molecular fragment in which at least onehydrogen atom bound to a carbon atom is replaced with one or moresubstituents that are functional groups such as hydroxyl, alkoxy,alkylthio, phosphino, amino, halo, silyl, and the like. Illustrativetertiary amines can include, but are not limited to, trimethylamine,triethylamine, triethanolamine, any combination thereof, or any mixturethereof. Illustrative polymeric tertiary amines can include, but are notlimited to, poly(N-methyl-diallyl amine), poly(N-dimethyl-vinyl amine),copolymers of N-dimethyl-vinyl amine, any combination thereof, or anymixture thereof. Illustrative polyamines can include, but are notlimited to, diethylenetriamine (“DETA”), triethylenetetramine (“TETA”),tetraethylenepentamine (“TEPA”). Other polyamines can include, forexample, 1,3-propanediamine, 1,4-butanediamine, polyamidoamines, andpolyethylenimines.

Illustrative phosphates can be or include, but are not limited to,potassium, phosphate, sodium phosphate, ammonium phosphate, or anycombination or mixture thereof. Illustrative bisulfites can include, butare not limited to, sodium bisulfite. Illustrative metabisulfites can beor include, but are not limited to, sodium metabisulfite, potassiummetabisulfite, or any combination or mixture thereof. Illustrativecyanamides can include, but are not limited to, cyanamide, calciumcyanamide, sodium hydrogen cyanamide, any combination thereof, or anymixture thereof.

The amount of catalyst, if present in the free radical precursor, canwidely vary. For example, the amount of catalyst in the mixture can befrom a low of about 0.00001 wt %, about 0.0001 wt %, about 0.001 wt %,about 0.01 wt %, or about 0.1 wt % to about 0.5 wt %, about 1 wt %,about 3 wt %, about 5 wt %, about 10 wt %, or about 20 wt %, based onthe dry weight of the lignocellulose substrates, with suitable rangesincluding the combination of any two values. In another example, theamount of catalyst in the mixture can be from about 0.01 wt % to about1.5 wt %, about 0.1 wt % to about 1.3 wt %, about 0.05 wt % to about 0.5wt %, about 0.07 wt % to about 0.4 wt %, about 0.05 wt % to about 5 wt%, based on the dry weight of the lignocellulose substrates. In anotherexample, the amount of the catalyst in the mixture can be about 0.001 wt% to about 0.5 wt %, about 0.15 wt % to about 0.35 wt %, about 0.1 wt %to about 0.4 wt %, about 0.1 wt % to about 2 wt %, about 0.05 wt % toabout 3 wt %, about 0.05 wt % to about 0.35 wt %, about 0.1 wt % toabout 4.5 wt %, about 0.15 wt % to about 4 wt %, about 0.05 wt % toabout 3 wt %, or about 0.01 wt % to about 3.5 wt %, based on the dryweight of the lignocellulose substrates.

In one or more embodiments, the amount of the metal, if present in thecatalyst, that can remain bound to the complexing agent until themixture is heated, e.g., to a temperature of about 60° C. to about 300°C., can be at least at least 11%, at least 13%, at least 15%, at least20%, at least 25%, at least 30%, at least 35%, at least 40%, at least45%, at least 50%, at least 55%, at least 60%, at least 65%, or at least70% of the amount of metal that was initially present in the mixture andbound to the complexing agent. In another example, the amount of themetal, if present in the catalyst, that can remain bound to thecomplexing agent until the mixture is heated, e.g., to a temperature ofabout 60° C. to about 300° C., can be about 11% to about 95%, about 15%to about 85%, about 20% to about 90%, about 30% to about 80%, about 11%to about 100%, about 35% to about 75%, about 40% to about 70%, or about30% to about 95% of the amount of the metal initially present in themixture and bound to the complexing agent.

The catalyst, if combined with a liquid medium, can have a totalconcentration of solids ranging from about 0.001 wt % to about 99.9 wt%. Preferably, if the catalyst is combined with a liquid medium, thecatalyst and liquid medium mixture can have a concentration of solidsfrom a low of about 0.1 wt %, about 0.5 wt %, about 1 wt %, or about 2wt % to a high of about 4 wt %, about 5 wt %, about 6 wt %, about 7 wt%, or about 8 wt %, based on the combined weight of the catalyst and theliquid medium, with suitable ranges including the combination of any twovalues.

The oxidant, if present in the free radical precursor, can be or includeany suitable oxidant or combination of oxidants. The oxidant can be asolid, liquid, gas, or multi-phase. Illustrative oxidants can include,but are not limited to, inorganic and/or organic peroxy compounds,ozonides, halogen containing oxidants, any combination thereof, or anymixture thereof. Illustrative inorganic peroxy compounds can include,but are not limited to, hydrogen peroxide, hydrogen peroxide generatingcompounds, e.g., alkali metal salts of percarbonate, perborate,peroxysulfate, peroxyphosphate, and/or peroxysilicate, and/orcorresponding weak acids. Illustrative organic peroxy compounds caninclude, but are not limited to, t-butyl peroxide, benzoyl peroxide,peroxy carboxylic acids, peracetic acid, perbenzoic acid,hydroperoxides, e.g., t-butyl hydroperoxides, or any combination ormixture thereof. Illustrative halogen containing oxidants can include,but are not limited to, alkali metal chlorite, alkali metalhypochlorite, chlorine dioxide, and/or a chloro sodium salt of cyanuricacid. An illustrative ozonide can include, but is not limited to,dimethyloxirane.

The oxidant can be combined with one or more liquid mediums. Forexample, the oxidant can be or include an aqueous solution of hydrogenperoxide. The concentration of oxidant, e.g., hydrogen peroxide,combined with a liquid medium, e.g., water, can be from a low of about 1wt %, about 3 wt %, about 5 wt %, about 10 wt %, about 15 wt %, about 20wt %, about 25 wt %, or about 30 wt % to a high of about 50 wt %, about60 wt %, about 70 wt %, about 80 wt %, about 90 wt %, or about 98 wt %,based on the combined weight of the oxidant and the liquid medium, withsuitable ranges including the combination of any two values.

The amount of oxidant present in the mixture can depend, at least inpart, on the particular oxidant, catalyst, lignocellulose substrates,and/or, if present, the compound having at least two hydrogen atoms thatare abstractable in the presence of hydroxyl radicals and, thus, canwidely vary. For example, the amount of oxidant in the mixture can befrom about 1 wt % to about 200 wt %, based on the dry weight of thelignocellulose substrates. In another example, the amount of oxidant inthe mixture can be from a low of about 1 wt %, about 5 wt %, about 10 wt%, or about 20 wt % to a high of about 80 wt %, about 100 wt %, about120 wt %, or about 150 wt %, based on the dry weight of thelignocellulose substrates, with suitable ranges including thecombination of any two values. In another example, the oxidant can bepresent in the mixture in an amount from about 0.1 wt % to about 30 wt%, about 1 wt % to about 20 wt %, about 5 wt % to about 50 wt %, about10 wt % to about 70 wt %, about 0.5 wt % to about 25 wt %, about 3 wt %to about 6 wt %, or about 2 wt % to about 8 wt %, based on the dryweight of the lignocellulose substrates. In still another example, theoxidant can be present in the mixture in amount of about 0.1 wt % toabout 10 wt %, about 1 wt % to about 12 wt %, about 2 wt % to about 9 wt%, about 3 wt % to about 9 wt %, about 5 wt % to about 15 wt %, about 4wt % to about 6 wt %, about 8 wt % to about 20 wt %, or about 2 wt % toabout 10 wt %, based on the dry weight of the lignocellulose substrates.

In one or more embodiments, the amount of oxidant, if present as or inthe free radical precursor, that can remain present until the mixture isheated, e.g., to a temperature of at least 60° C. to about 300° C., canbe at least at least 11%, at least 13%, at least 15%, at least 20%, atleast 25%, at least 30%, at least 35%, at least 40%, at least 45%, atleast 50%, at least 55%, at least 60%, at least 65%, or at least 70% ofthe amount of oxidant initially present in the mixture. In anotherexample, the amount of the oxidant, if present in the free radicalprecursor, that can remain present until the mixture is heated, e.g., toa temperature of about 60° C. to about 300° C., can be about 11% toabout 95%, about 15% to about 85%, about 20% to about 90%, about 30% toabout 80%, about 11% to about 100%, about 35% to about 75%, about 40% toabout 70%, or about 30% to about 95% of the amount of the oxidantinitially present in the mixture.

The optional one or more compounds having at least two hydrogen atomsthat are abstractable in the presence of hydroxyl radicals can be orinclude, but are not limited to, one or more lignins, one or moretannins, one or more novolac resins, one or more modified phenolformaldehyde resins, bis-phenol A, humic acids, or any combination ormixture thereof. If two or more compounds having at least two hydrogenatoms that are abstractable in the presence of hydroxyl radicals arepresent, the two or more compounds having at least two hydrogen atomsthat are abstractable in the presence of hydroxyl radicals can bepresent in any amount with respect to one another. The one or morecompounds having at least two hydrogen atoms that are abstractable inthe presence of hydroxyl radicals can be in the form of a solid, aliquid, or a “two phase” or solid/liquid mixture.

Lignin is a polymeric substance that can include substituted aromaticsfound in plant and vegetable matter associated with cellulose and otherplant constituents. Illustrative plant and vegetable matter can include,but is not limited to, straw, hemp, sisal, cotton stalk, wheat, bamboo,sabai grass, rice straw, banana leaves, paper mulberry (i.e., bastfiber), abaca leaves, pineapple leaves, esparto grass leaves, fibersfrom the genus Hesperaloe in the family Agavaceae jute, salt waterreeds, palm fronds, flax, ground nut shells, hardwoods, softwoods,recycled fiberboards such as high density fiberboard, medium densityfiberboard, low density fiberboard, oriented strand board,particleboard, or any combination thereof. For example, the plant mattercan be or include wood, for example hardwoods, softwoods, or acombination thereof. Illustrative types of wood can include, but are notlimited to, alder, ash, aspen, basswood, beech, birch, cedar, cherry,cottonwood, cypress, elm, fir, gum, hackberry, hickory, maple, oak,pecan, pine, poplar, redwood, sassafras, spruce, sycamore, walnut, andwillow.

The lignin can be extracted, separated, or otherwise recovered from thewood, plant, and/or vegetable matter using any of a number of wellestablished processes. For example, in the pulp and paper industry,lignin-containing materials such as wood, straw, corn stalks, bagasse,and other vegetable and plant tissues can be processed to recover thecellulose or pulp via the well known kraft or sulfate process or thewell known sulfite process. The residual pulping liquors that includethe lignin as a by-product can be a source of lignin. The chemicalstructure of lignin can vary and the variation can depend, at least inpart, on the particular plant from which the lignin is recovered from,location the plant was grown, and/or on the particular method used inrecovery or isolation of the lignin from the plant and/or vegetablematter. Lignin can include active groups, such as active hydrogensand/or phenolic hydroxyl groups through which crosslinking or bridgingcan be effected.

One process for recovering lignin can be or include the process commonlyreferred to as the organosolv process. The organosolve process uses anorganic solvent to solubilize lignin and hemicelluloses. The organosolveprocess can include contacting lignocellulose material, e.g., wood chipsor particles, with an aqueous organic solvent at a temperature from alow of about 130° C., about 140° C., or about 150° C. to a high of about200° C., about 220° C., or about 230° C. The lignin can break down byhydrolytic cleavage of alpha aryl-ether links into fragments that can besolubilized in the solvent system. Illustrative solvents can include,but are not limited to, acetone, methanol, ethanol, butanol, ethyleneglycol, formic acid, acetic acid, any combination thereof, or anymixture thereof. The aqueous organic solvent can have a concentration ofthe solvent in water from a low of about 30 wt %, about 40 wt % or about50 wt % to a high of about 70 wt %, about 80 wt %, or about 90 wt %.

Since the lignin separated from the plant can be chemically altered fromthat found in the plant, the term “lignin,” can also refer to ligninproducts obtained upon separation from the cellulose or recovered fromthe plant matter. For example, in a sulfite pulping process, thelignocellulose material can be digested with a bisulfite or sulfiteresulting in the at least partial sulfonation of the lignin. As such,the lignin can optionally be subjected to further cleavage and/or othermodifications such as alkaline treatment or reaction with otherconstituents to decrease the sulfonate or sulfur content and/or increasethe active groups. For example, the lignin can be processed such that ithas a phenolic hydroxyl content from about 1.5 wt % to about 5 wt % andless than about 3 wt % sulfonate sulfur. In other methods of recovery orseparation of lignin from wood, plant, or vegetable material, the ligninmay not be sulfonated, but could be chemically altered somewhat in someother manner. For example, in residual pulping liquors obtained insulfate or other alkaline pulping processes, the lignin can be presentas an alkali metal salt dissolved in the alkaline, aqueous liquor andcan generally include a sufficient phenolic hydroxyl content to requireno further modification. However, the alkali or kraft lignin can befurther reacted with other constituents to further increase the activegroups. “Hydrolysis lignin” that can be recovered from the hydrolysis oflignocellulose materials in the manufacture of sugar, for example, canalso be altered somewhat from that found in the plant. As suchhydrolysis lignin can be further modified to solubilize the lignin aswell as to increase the phenolic hydroxyl content. Also, the ligninproducts such as residual pulping liquor may be subjected to varioustreatments such as, for example, acid, alkaline or heat treatments orreacted with the other chemicals which may further alter somewhat thelignin constituents.

The residual pulping liquors or the lignin products produced in theseparation or recovery of lignin from the plant matter can includelignin of various weight average molecular weights (Mw) ranging fromabout 300 to over 100,000. For example, the lignin can have a Mw from alow of about 500, about 1,000, about 5,000, about 10,000, about 15,000,or about 20,000 to a high of about 30,000, about 45,000, about 55,000,about 70,000, about 80,000, about 85,000, about 90,000, or about 95,000,with suitable ranges including the combination of any two values. Inanother example, the lignin can have a Mw from a low of about 300, about500, about 800, about 900, about 1,000, or about 1,100 to a high ofabout 1,300, about 1,500, about 1,900, about 2,300, about 2,500, about2,700, about 3,000, about 3,300, about 3,500, about 3,700, about 4,000,about 4,300, about 4,500, about 4,700, or about 5,000, with suitableranges including the combination of any two values. In another example,the lignin can have a Mw from a about 500 to about 30,000, about 1,000to about 15,000, about 800 to about 6,000, about 2,000 to about 12,000,about 400 to about 10,000, or about 600 to about 8,000. In anotherexample, the Mw of the lignin can be from about 600 to about 4,500,about 350 to about 1,100, about 750 to about 2,500, about 950 to about3,100, about 1,500 to about 3,400, or about 1,800 to about 4,200.

The liquors from which the lignin can be recovered can also include oneor more other constituents in addition to the lignin. For example, inthe sulfite pulping process, the spent sulfite liquor can includelignosulfonates that can be present as salts of cations, such asmagnesium, calcium, ammonium, sodium and/or other cations. The spentsulfite liquor solids can include about 40 wt % to about 65 wt %lignosulfonates with the remainder being carbohydrates and other organicand inorganic constituents dissolved in the liquor. Lignin productsproduced by other pulping processes can also include other materialssuch as carbohydrates, degradation products of carbohydrates, andresinous materials which are separated from the cellulosic materialswith the lignin. It should be noted that it is not necessary to separatethe lignin from the other constituents that can be present.

Suitable lignin material can include, but is not limited to, lignin inits native or natural state, i.e., non-modified or unaltered lignin,lignosulfonates, or any combination or mixture thereof. Suitablelignosulfonates can include, but are not limited to, ammoniumlignosulfonate, sodium lignosulfonate, calcium lignosulfonate, magnesiumlignosulfonate, or any combination or mixture thereof.

Suitable processes for isolating or otherwise separating lignin orlignin containing products form wood, plant, vegetable, or other lignincontaining matter can include those discussed and described in U.S. Pat.Nos. 1,856,567; 2,525,433; 2,680,113; 2,690,973; 3,094,515; 3,158,520;3,503,762; 3,585,104; 3,726,850; 3,769,272; 3,841,887; 4,100,016;4,131,564; 4,184,845; 4,308,203; 4,355,996; 4,470,876; 4,740,591; and4,764,596; U.S. Patent Application Publication Nos.: 2011/0294991; andWO Publication Nos. WO1992/018557A1, WO1993/021260A2; WO1994/024192A1;WO2005/062800A2; WO2006/031 175 A1; and WO2011/150508. Commerciallyavailable lignin can include, but is not limited to, lignosulfonatesavailable from Tembec (Canada).

The novolac resin can be produced by reacting a phenol component with analdehyde component or aldehyde compound(s) in the presence of an acidcatalyst. The phenol component of the novolac resin can include avariety of substituted phenolic compounds, unsubstituted phenoliccompounds, or any combination of substituted and/or unsubstitutedphenolic compounds. For example, the phenol component can be phenolitself, i.e., mono-hydroxy benzene. Examples of substituted phenols caninclude, but are not limited to, alkyl-substituted phenols such as thecresols and xylenols; cycloalkyl-substituted phenols such as cyclohexylphenol; alkenyl-substituted phenols; aryl-substituted phenols such asp-phenyl phenol; alkoxy-substituted phenols such as3,5-dimethyoxyphenol; aryloxy phenols such as p-phenoxy phenol; andhalogen-substituted phenols such as p-chlorophenol. Dihydric phenolssuch as catechol, resorcinol, hydroquinone, bis-phenol A and bis-phenolF also can also be used. Specific examples of suitable phenoliccompounds (phenol components) for replacing a portion or all of thephenol used in preparing a novolac resin can include, but are notlimited to, bis-phenol A, bis-phenol F, o-cresol, m-cresol, p-cresol, 3,5-5 xylenol, 3,4-xylenol, 3,4,5-trimethylphenol, 3-ethyl phenol,3,5-diethyl phenol, p-butyl phenol, 3,5-dibutyl phenol, p-amyl phenol,p-cyclohexyl phenol, p-octyl phenol, 3,5 dicyclohexyl phenol, p-phenylphenol, p-phenol, 3,5-dimethoxy phenol, 3,4,5 trimethoxy phenol,p-ethoxy phenol, p-butoxy phenol, 3-methyl-4-methoxy phenol, p-phenoxyphenol, naphthol, anthranol and substituted derivatives thereof.Preferably, about 80 wt % or more, about 90 wt % or more, or about 95 wt% or more of the phenol component includes phenol (mono-hydroxybenzene).

Illustrative aldehyde compounds can include the so-called maskedaldehydes or aldehyde equivalents, such as acetals or hemiacetals.Suitable aldehydes can be represented by the general formula R′CHO,where R′ is a hydrogen or a hydrocarbon radical generally having 1-8carbon atoms. Specific examples of suitable aldehyde compounds caninclude, but are not limited to, formaldehyde, acetaldehyde,propionaldehyde, butyraldehyde, furfuraldehyde, benzaldehyde, anycombination thereof, or any mixture thereof. As used herein, the term“formaldehyde” can refer to formaldehyde, formaldehyde derivatives,other aldehydes, or combinations thereof. Preferably, the aldehydecomponent is formaldehyde. One or more difunctional aldehydes can alsobe used to produce the novolac resin, and could advantageously be usedto introduce cross-links ultimately into the at least partially curednovolac resin.

The aldehyde can be used in many forms such as solid, liquid, and/orgas. Considering formaldehyde in particular, the formaldehyde can be orinclude paraform (solid, polymerized formaldehyde), formalin solutions(aqueous solutions of formaldehyde, sometimes with methanol, in 37percent, 44 percent, or 50 percent formaldehyde concentrations),Urea-Formaldehyde Concentrate (“UFC”), and/or formaldehyde gas in lieuof or in addition to other forms of formaldehyde can also be used. Inanother example, the aldehyde can be or include a pre-reactedurea-formaldehyde mixture having a urea to formaldehyde weight ratio ofabout 1:2 to about 1:3.

A molar ratio of formaldehyde to phenol used to produce the novolacresin can be from about 0.5 to about 0.95 or more preferably from about0.7 to about 0.85. The reaction between the phenol and the formaldehydeto produce the novolac resin can be carried out in the presence of anacid catalyst under acidic conditions. Suitable acid catalysts caninclude, but are not limited to, oxalic acid, sulfuric acid, p-toluenesulfuric acid, hydrochloric acid, salicylic acid, mineral acids andsalts thereof, any combination thereof, or any mixture thereof. Mixedcatalyst systems, such as ZnOAc/oxalic acid and other divalent metalcompounds, e.g., acetates, can be used to prepare “high-ortho” novolacresins. Divalent metal compounds can include Ca, Mg, Zn, Cd, Pb, Cu, CO,and Ni. Preferred catalysts include oxalic acid, sulfuric acid,p-toluene sulfonic acid, and ZnOAc/oxalic acid. Most preferably, thecatalyst is oxalic acid or ZnOAc/oxalic acid.

The amount of acid catalyst used to produce the novolac resin can besufficient to catalyze the reaction between the phenol and formaldehydeto produce the novolac resin. The phenol/formaldehyde reaction can beconducted in about 1 to about 6 hours, e.g., in about 2 to about 4hours. The phenol/formaldehyde reaction can be carried out at atemperature from about 80° C. to about 100° C., e.g., about 95° C. toabout 100° C. The reaction can be carried out at atmospheric pressure,although increased pressure can be utilized to permit the application ofhigher temperatures and, therefore, faster reaction rates andaccordingly shorter reaction times.

The novolac resin can be treated to remove water and/or other volatileorganic materials by heating, such as by distillation. After thistreatment, the free phenol can be about 0.001% to about 2.0%, preferablyabout 0.001% to about 0.5%. Distillation of the resulting novolac resincan be performed at atmospheric pressure by heating up to about 140° C.,and then under a vacuum until the resin reaches a temperature of about180° C. to about 220° C. Other suitable methods for treating the resinvia heat can include thin-film evaporators. The resulting molten novolacresin can be cooled to a temperature below about 100° C.

If desired, the novolac resin can be neutralized. Neutralization of thenovolac resin can be accomplished by the addition of one or more basesor base compounds, such as sodium hydroxide and/or potassium hydroxide,or its equivalent. The base compound can be added in an amountsufficient to raise the pH of the novolac resin to between about 5 toabout 9, e.g., about 6 to about 8. Typically, about 10 wt % to about 30wt % of water, based on the total resin solids, can be added. Suitablenovolac resins and inverted novolac resins can be as discussed anddescribed in U.S. Pat. No. 5,670,571 and U.S. Patent ApplicationPublication No. 2008/0280787.

As used herein, the term “tannin” refers to both hydrolyzable tanninsand condensed tannins. As such, the compound having at least twohydrogen atoms that are abstractable in the presence of hydroxylradicals can be or include hydrolyzable tannins, condensed tannins, or acombination of hydrolyzable tannins and condensed tannins. Illustrativegenera of shrubs and/or trees from which suitable tannins can be derivedcan include, but are not limited to, Acacia, Castanea, Vachellia,Senegalia, Terminalia, Phyllanthus, Caesalpinia, Quercus, Schinopsis,Tsuga, Rhus, Juglans, Carya, and Pinus, any combination thereof, or anymixture thereof. In another example, genera from which suitable tanninscan be derived can include, but are not limited to, Schinopsis, Acacia,or a combination thereof. In another example, genera from which suitabletannins can be derived can include, but are not limited to, Pinus,Carya, or a combination thereof.

Hydrolyzable tannins are mixtures of simple phenols such as pyrogalloland ellagic acid and of esters of a sugar, e.g., glucose, with gallicand digallic acids. Illustrative hydrolyzable tannins can include, butare not limited to, extracts recovered from Castanea sativa, (e.g.,chestnut), Terminalia and Phyllantus (e.g., myrabalans tree species),Caesalpinia coriaria (e.g., divi-divi), Caesalpinia spinosa, (e.g.,tara), algarobilla, valonea, and Quercus (e.g., oak). Condensed tanninsare polymers formed by the condensation of flavans. Condensed tanninscan be linear or branched molecules. Illustrative condensed tannins caninclude, but are not limited to Acacia mearnsii (e.g., wattle or mimosabark extract), Schinopsis (e.g., quebracho wood extract), Tsuga (e.g.,hemlock bark extract), Rhus (e.g., sumach extract), Juglans (e.g.,walnut), Carya illinoinensis (e.g., pecan), and Pinus (e.g., Radiatapine, Maritime pine, bark extract species).

The condensed tannins typically include about 70 wt % to about 80 wt %active phenolic ingredients (the “tannin fraction”) and the remainingingredients (the “non-tannin fraction”) typically include, but are notlimited to, carbohydrates, hydrocolloid gums, and amino and/or iminoacid fractions. The condensed tannins can be used as recovered orextracted from the organic matter or the condensed tannins can bepurified, e.g., about 95 wt % or more active phenolic ingredients.Hydrolyzable tannins and condensed tannins can be extracted from thestarting material, e.g., trees and/or shrubs, using well establishedprocesses. A more detailed discussion of tannins is discussed anddescribed in the Handbook of Adhesive Technology, Second Edition, CRCPress, 2003, chapter 27, “Natural Phenolic Adhesives I: Tannin,” and inMonomers, Polymers and Composites from Renewable Resources, Elsevier,2008, chapter 8, “Tannins: Major Sources, Properties and Applications.”

The condensed tannins can be classified or grouped into one of two maincategories, namely, those containing a resorcinol unit and thosecontaining a phloroglucinol unit. Illustrative tannins that include theresorcinol unit include, but are not limited to, black wattle tanninsand quebracho tannins. The resorcinol unit can be represented by formulaI below.

The resorcinol group is shown within the box overlaying the unitstructure of black wattle and quebracho tannins in formula II below. Forsimplicity, the structure of black wattle and quebracho tannins isrepresented by their flavonoid unit structure.

Illustrative tannins that include the phloroglucinol unit include, butare not limited to, pecan tannins and pine tannins. The phloroglucinolunit can be represented by formula III below.

The phloroglucinol unit is shown within the box overlaying the unitstructure of pecan and pine tannins in formula IV below. For simplicity,the structure of pecan and pine tannins is represented by theirflavonoid unit structure.

Phloroglucinol is known for higher reactivity than resorcinol. As such,tannins that include the phloroglucinol unit are more reactive thantannins that include the resorcinol unit.

The tannins can have an acidic pH. For example, the pH of the tanninscan be from a low of about 3, about 3.5, or about 4 to a high of about5, about 5.5, about 6, or about 6.5, with suitable ranges including thecombination of any two values. The tannins can have resorcinol and/orphloroglucinol functional groups. Suitable, commercially availabletannins can include, but are not limited to, black wattle tannin,quebracho tannin, hemlock tannin, sumach tannins, pecan tannin, mimosatannin, pine tannins, any combination thereof, or any mixture thereof.

Illustrative modified phenol formaldehyde resins can include ARYLZENE®,which can be represented by the general formula IX:

Other illustrative modified phenol formaldehyde resins can be or includethose discussed and described in U.S. Pat. Nos. 5,674,970; 5,739,259;5,756,642; 5,756,655; 5,770,750; 5,773,552; 5,837,798; 5,889,137;6,166,151; 6,291,077; 6,399,740; and 6,569,953.

Humic acid can be represented by the general formula X:

The compound having at least two hydrogen atoms that are abstractable inthe presence of hydroxyl radicals, e.g., the tannin, lignin, and/ornovolac resin, can be combined with a liquid medium. The compound havingat least two hydrogen atoms that are abstractable in the presence ofhydroxyl radicals when combined with a liquid medium can have a totalconcentration of solids ranging from about 1 wt % to about 99 wt %. Forexample, the compound having at least two hydrogen atoms that areabstractable in the presence of hydroxyl radicals combined with a liquidmedium can have a concentration of solids from a low of about 5 wt %,about 10 wt %, about 15 wt %, or about 20 wt % to a high of about 40 wt%, about 50 wt %, about 60 wt %, about 70 wt %, or about 80 wt %, basedon the combined weight of the compound having at least two hydrogenatoms that are abstractable in the presence of hydroxyl radicals and theliquid medium. In another example, the compound having at least twohydrogen atoms that are abstractable in the presence of hydroxylradicals combined with a liquid medium can have a concentration ofsolids from about 40% to about 60%, about 45% to about 55%, or about 47%to about 50%. In another example, the compound having at least twohydrogen atoms that are abstractable in the presence of hydroxylradicals combined with a liquid medium can have a concentration ofsolids from about 10% to about 30%, about 15% to about 35%, about 20% toabout 40%, about 25% to about 45%, about 20% to about 50%, or about 35%to about 55%.

As used herein, the solids concentration or solids content of thecompound having at least two hydrogen atoms that are abstractable in thepresence of hydroxyl radicals, e.g., lignin, tannin, and/or novolacresin, as understood by those skilled in the art, can be measured bydetermining the weight loss upon heating a small sample, e.g., 1-5 gramsof the compound having at least two hydrogen atoms that are abstractablein the presence of hydroxyl radicals, to a suitable temperature, e.g.,125° C., and a time sufficient to remove any liquid combined therewith.By measuring the weight of the sample before and after heating, thepercent solids in the sample can be directly calculated or otherwiseestimated.

Any one or more of the compounds having at least two hydrogen atoms thatare abstractable in the presence of hydroxyl radicals can be modifiedwith one or more compounds having one or more carbon-carbon double bondsand one or more reactive functional groups. For example, the mixture caninclude one or more modified compounds having at least two hydrogenatoms that are abstractable in the presence of hydroxyl radicalsproduced by at least partially reacting one or more unsaturated monomershaving one or more reactive functional groups with the one or morecompounds having at least two hydrogen atoms that are abstractable inthe presence of hydroxyl radicals, e.g., the lignin, tannin, novolacresin, modified phenol formaldehyde resin, bis-phenol A, and/or humicacid. Any suitable compounds having one or more carbon-carbon doublebonds and one or more reactive functional groups or combination ofcompounds having one or more carbon-carbon double bonds and one or morereactive functional groups can be used to produce the modified compoundhaving at least two hydrogen atoms that are abstractable in the presenceof hydroxyl radicals. Preferably the compounds having one or morecarbon-carbon double bonds and one or more reactive functional groupsare nonionic. Illustrative compounds having one or more carbon-carbondouble bonds and one or more reactive functional groups can include, butare not limited to, one or more unsaturated glycidyl ethers, one or moreunsaturated glycidyl esters, one or more unsaturated mono-epoxides, oneor more unsaturated methylol compounds, maleic anhydride, anycombination thereof, or any mixture thereof.

Illustrative unsaturated glycidyl ethers can be represented by generalformula V:

where R can be an ethylenically unsaturated radical such as vinyl,allyl, alkenyl, and the like. Suitable glycidyl ethers can include, butare not limited to, vinyl glycidyl ether, isopropenyl glycidyl ether,oleyl glycidyl ether, allyl glycidyl ether, p-vinylbenzyl glycidylether, o-allyl phenyl glycidyl ether, butenyl glycidyl ether,4-vinylcyclohexyl glycidyl ether, abietylglycidyl ether,cyclohexeneylmethyl glycidyl ether, methallyl glycidyl ether, anycombination thereof, or any mixture thereof.

Illustrative unsaturated glycidyl esters can be represented by generalformula VI:

where R can be an unsaturated, unsubstituted alkyl radical having fromtwo to 19 carbon atoms. Suitable glycidyl esters can include, but arenot limited to, glycidyl methacrylate, glycidyl acrylate, glycidylcrotonate, glycidyl oleate, di-glycidyl maleate, di-glycidyl fumarate,any combination thereof, or any mixture thereof.

Illustrative unsaturated mono-epoxides can include, but are not limitedto, linear or cycloaliphatic epoxy compounds, where the unsaturation isterminal. Suitable unsaturated mono-epoxides can be represented bygeneral formula VII:

where R can be a single bond or an alkylene optionally containing alkylpendant groups; R¹, R², and R³ can independently be hydrogen, alkylstraight, branched or cyclic, or any two of R¹, R², or R³ can bealkylene and combined to form a 5 to 12 carbon cyclic ring, optionallycontaining alkyl pendants; and the number of carbon atoms in R, R′, R²,and R³ can be such that the total number of carbon atoms in the epoxideis from 4 to 50. Suitable unsaturated mono-epoxides can include, but arenot limited to, 4-vinyl cyclohexene oxide, 1-methyl-4-isopropenylcyclohexene monoxide, butadiene monoxide, any combination thereof, orany mixture thereof.

Illustrative unsaturated methylol compounds can be represented by thegeneral formula VIII:

where R, R₁, R₂, and R₃ can independently be hydrogen or a hydrocarbylgroup, e.g., an alkyl group, containing from about 1 to about 6 carbonatoms. For example, an alkyl group can include from 1 to 4 carbon atoms.In at least one example, R, R₁, R₂, and R₃ can each independently bemethyl or hydrogen. Suitable unsaturated methylol compounds can include,but are not limited to, N-methylol acrylamide, N-methylolmethacrylamide, N-methylol crotonamide, any combination thereof, or anymixture thereof. The N-methylol ethylenically unsaturated amide can bein the form of an aqueous solution.

In at least one example, the modified compound having at least twohydrogen atoms that are abstractable in the presence of hydroxylradicals can be free or essentially free of any anionic monomers. Forexample, the modified compound having at least two hydrogen atoms thatare abstractable in the presence of hydroxyl radicals can contain lessthan about 3 wt %, less than about 2.5 wt %, less than about 2 wt %,less than about 1.5 wt %, less than about 1 wt %, less than about 0.7 wt%, less than about 0.5 wt %, less than about 0.3 wt %, less than about0.1 wt %, less than about 0.05 wt %, or less than about 0.01 wt %anionic monomers. In at least one example, the modified compound havingat least two hydrogen atoms that are abstractable in the presence ofhydroxyl radicals can be free or essentially free of any ionic monomers.For example, the modified compound having at least two hydrogen atomsthat are abstractable in the presence of hydroxyl radicals can containless than about 3 wt %, less than about 2.5 wt %, less than about 2 wt%, less than about 1.5 wt %, less than about 1 wt %, less than about 0.7wt %, less than about 0.5 wt %, less than about 0.3 wt %, less thanabout 0.1 wt %, less than about 0.05 wt %, or less than about 0.01 wt %ionic monomers. In at least one other example the modified compoundhaving at least two hydrogen atoms that are abstractable in the presenceof hydroxyl radicals can be free or essentially free of any anionic andionic monomers. For example, the modified compound having at least twohydrogen atoms that are abstractable in the presence of hydroxylradicals can contain less than about 3 wt %, less than about 2.5 wt %,less than about 2 wt %, less than about 1.5 wt %, less than about 1 wt%, less than about 0.7 wt %, less than about 0.5 wt %, less than about0.3 wt %, less than about 0.1 wt %, less than about 0.05 wt %, or lessthan about 0.01 wt % anionic and ionic monomers. As used herein, theterms “essentially free of anionic monomers” and “essentially free ofionic monomers” means the modified compound having at least two hydrogenatoms that are abstractable in the presence of hydroxyl radicals doesnot include any intentionally added anionic monomers or ionic monomers,respectively. Said another way, the terms “essentially free of anionicmonomers” and “essentially free of ionic monomers” means the modifiedcompound having at least two hydrogen atoms that are abstractable in thepresence of hydroxyl radicals may include anionic monomers and/or ionicmonomers present as an impurity.

The amount of the compound having at least two hydrogen atoms that areabstractable in the presence of hydroxyl radicals, if present inmixture, can widely vary. For example, the amount of the compound havingat least two hydrogen atoms that are abstractable in the presence ofhydroxyl radicals in the mixture can be from about 0.01 wt % to about 50wt %, based on the dry weight of the lignocellulose substrates. Inanother example, the amount of the compound having at least two hydrogenatoms that are abstractable in the presence of hydroxyl radicals in themixture can be from a low of about 0.05 wt %, about 0.1 wt %, about 0.5wt %, about 1 wt %, about 2 wt %, about 3 wt %, about 5 wt %, or about 7wt % to a high of about 15 wt %, about 20 wt %, about 25 wt %, or about30 wt %, based on the dry weight of the lignocellulose substrates, withsuitable ranges including the combination of any two values. In anotherexample, the amount of the compound having at least two hydrogen atomsthat are abstractable in the presence of hydroxyl radicals in themixture can be from a low of about 0.1 wt %, about 0.5 wt %, about 1 wt%, about 3 wt %, or about 5 wt % to a high of about 10 wt %, about 13 wt%, about 15 wt %, about 17 wt %, or about 20 wt %, based on the dryweight of the lignocellulose substrates, with suitable ranges includingthe combination of any two values. In another example, the amount of thecompound having at least two hydrogen atoms that are abstractable in thepresence of hydroxyl radicals in the mixture can be from about 1 wt % toabout 15 wt %, about 5 wt % to about 15 wt %, about 8 wt % to about 13wt %, about 7 wt % to about 12 wt %, or about 5 wt % to about 25 wt %,based on the dry weight of the lignocellulose substrates.

The lignocellulose substrates can include any one or more of the plantand vegetable materials discussed and described above with reference tothe source for the lignins and tannins. As used herein, the term“lignocellulose” refers to a material that includes lignin andcellulose, hemicelluose, or a combination of cellulose andhemicelluloses. The starting material, from which the lignocellulosesubstrates can be or can be derived from, can be shaped, reduced, orotherwise formed to the appropriate dimensions by various processes suchas hogging, grinding, hammer milling, tearing, shredding, and/orflaking. Other processes for producing the substrates can includeskiving, cutting, slicing, and/or sawing. Suitable forms of thelignocellulose substrates can include, but are not limited to, chips,flakes, wafers, fibers, powder, shavings, sawdust or dust, veneer,strands, and/or the like. Accordingly, the term “substrate” when used inconjunction with “lignocellulose” refers to lignocellulose material orlignocellulose containing material having any desired shape such aschips, flakes, fibers, powder, shavings, sawdust or dust, veneer,strands, and/or the like. Other suitable lignocellulose substrates caninclude, but are not limited to, wood chips, wood fibers, wood flakes,wood strands, wood wafers, wood shavings, wood particles, wood veneer,any combination thereof, or any mixture thereof.

The particular configuration of the substrates can be based, at least inpart, on the desired product. For example, particulates such as chips,fibers, shavings, sawdust or dust, or the like can be preferred forproducing particleboards, fiberboards, and the like. The substrates canhave a length from a low of about 0.05 mm, about 0.1 mm, about 0.2 mm toa high of about 1 mm, about 5 mm, about 10 mm, about 20 mm, about 30 mm,about 40 mm, about 50 mm, or about 100 mm, with suitable rangesincluding the combination of any two values. In another example,veneers, i.e., layers or sheets of wood, can be used for producingplywood, laminated veneer lumber, and the like. The veneers can have athickness from a low of about 0.8 mm, about 0.9 mm, about 1 mm, about1.1 mm or about 1.2 mm to a high of about 3 mm, about 4 mm, about 5 mm,about 6 mm, about 7 mm, about 8 mm, about 9 mm, or about 10 mm, withsuitable ranges including the combination of any two values.

The lignocellulose substrates can include liquid on, about, and/orwithin the substrates. For example, the lignocellulose substrates canhave a liquid, e.g., moisture, content from a low of about 1 wt %, about2 wt %, about 3 wt %, about 4 wt, or about 5 wt % to a high of about 7wt %, about 9 wt %, about 11 wt %, about 13 wt %, about 15 wt %, about17 wt %, about 19 wt %, about 21 wt %, about 23 wt %, about 25 wt %,about 27 wt %, about 29 wt %, about 31 wt %, about 33 wt %, about 35 wt%, or about 37 wt % based on a dry weight of the lignocellulosesubstrate, with suitable ranges including the combination of any twovalues. In another example, the lignocellulose substrates can have aliquid, e.g., moisture, content of about 1 wt % to about 10 wt %, about2 wt % to about 4 wt %, about 2 wt % to about 3 wt %, about 3 wt % toabout 6 wt %, about 5 wt % to about 10 wt %, about 6 wt % to about 8 wt%, or about 4 wt % to about 9 wt %. The lignocellulose substrates can befresh, i.e., not treated or dried, or dried and/or treated. For example,the lignocellulose substrates and/or the starting material from whichthe lignocellulose substrates were derived can be at least partiallydried. In another example, the lignocellulose substrates can be washedand/or leached with an aqueous medium such as water.

If any one or more of the components discussed and described hereininclude two or more different compounds, those two or more differentcompounds can be present in any ratio with respect to one another. Saidanother way, if the mixture includes a first and a second type oflignocellulose substrate, free radical precursor, and/or compound havingat least two hydrogen atoms that are abstractable in the presence ofhydroxyl radicals the amount of the first and second components can bepresent in any desired ratio. For example, if the oxidant is present inthe free radical precursor and includes a first oxidant and a secondoxidant, the mixture can have an oxidant composition that includes thefirst oxidant in an amount from about 1 wt % to about 99 wt % andconversely about 99 wt % to about 1 wt % of the second oxidant, based onthe total weight of the oxidant composition, i.e., the total weight ofthe first and second oxidants. In another example, the amount of thefirst oxidant can be from a low of about 5 wt %, about 10 wt %, about 15wt %, about 20 wt %, about 25 wt % about 30 wt %, about 35 wt %, about40 wt %, or about 45 wt % to a high of about 60 wt %, about 65 wt %,about 70 wt %, about 75 wt %, about 80 wt %, about 85 wt %, about 90 wt%, or about 95 wt %, based on the total weight of the first and secondoxidants.

One or more salts can optionally be combined with the lignocellulosesubstrates, the free radical precursor, and the optional compound havingat least two hydrogen atoms that are abstractable in the presence ofhydroxyl radicals. The amount of salt in the mixture, if present, can befrom a low of about 1 wt %, about 2 wt %, or about 3 wt % to a high ofabout 10 wt %, about 20 wt %, or about 30 wt %, based on the dry weightof the lignocellulose substrates, with suitable ranges including thecombination of any two values. The one or more salts can be combinedwith the lignocellulose substrates, catalyst, and/or oxidant in anyorder or sequence. Illustrative salts can include, but are not limitedto, Al, Ca, K, Na, Cu, Zn, Mg, Mn, Ba, and/or Li cations. Suitableanions can include, but are not limited to, carbonates, chlorides,nitrates, silicates, acetates, formates, sulphates, phosphates, and/orother forms.

Illustrative composite products discussed and described herein caninclude, but are not limited to, particleboard, fiberboard such asmedium density fiberboard (“MDF”) and/or high density fiberboard(“HDF”), plywood such as hardwood plywood and/or softwood plywood,oriented strand board (“OSB”), laminated veneer lumber (“LVL”),laminated veneer boards (“LVB”), engineered wood flooring, and the like.

The method of making one or more composite products can include acontinuous or semi-continuous blending process in which thelignocellulose substrates and the other components of the mixture, e.g.,the catalyst, oxidant, and the compound having at least two hydrogenatoms that are abstractable in the presence of hydroxyl radicals, can beintroduced to a blender at a first or introduction region, end, area, orother location(s) configured to receive the components and the mixturecan be withdrawn from the blender via one or more mixture recoveryoutlets. The blender can be configured to contain anywhere from a fewhundred kilograms to several thousand kilograms. For example, in asingle blender anywhere from a low of about 500 kg/hr, about 5,000kg/hr, about 10,000 kg/hr, or about 13,000 kg/hr to a high of about16,000 kg/hr, about 20,000 kg/hr, about 25,000 kg/hr, or about 30,000kg/hr of the mixture can be recovered from the blender. As the mixtureexits the blender, the mixture can be deposited onto a conveyor belt andcan be transported to one or more dryers, moistening systems, presses,and/or other processing equipment. For example, in at least one specificembodiment, a particle board product can be made blending a first or“face” mixture and a second or “core” mixture in a first and secondblend, respectively. The first blender can produce from about 13,600kg/hr to about 15,900 kg/hr of a “face” mixture and the second blendercan produce from about 18,100 kg/hr to about 20,400 kg/hr of a “core”mixture. The “face” and “core” mixtures can be used to produce aparticleboard panel or sheet, where the “face” mixture makes up theouter layers of the particleboard and the “core” mixture makes up theinner or core layer of the particleboard.

Referring to particleboard in particular, particleboard made accordingto one or more embodiments discussed and described herein can meet orexceed the requirements for H-1, H-2, H-3, M-0, M-1, M-S, M-2, M-3i,LD-1, and/or LD-2 grade particleboard as described in the AmericanNational Standards Institute (ANSI) for particleboard, i.e., ANSIA208.1-2009 Particleboard, approved Feb. 2, 2009. Particleboard madeaccording to one or more embodiments discussed and described herein canmeet or exceed the requirements for PBU, D-2, D-3, and/or M-3 as definedby the ANSI for particleboard, i.e., ANSI A208.1-2009 Particleboard,approved Feb. 2, 2009. For example, Tables A and B set out certainrequirements for the different grades of particleboard. Referring tooriented strand board (OSB) in particular, OSB made according to one ormore embodiments discussed and described herein can meet or exceed theU.S. Department of Commerce Voluntary Performance Standard PS 2.Referring to plywood in particular, plywood made according to one ormore embodiments discussed and described herein can meet or exceed theU.S. Department of Commerce Voluntary Performance Standard PS 1 and/orPS-2.

In one or more embodiments, one or more additives can be combined withthe lignocellulose substrates, free radical precursor, and optionallythe compound having at least two hydrogen atoms that are abstractable inthe presence of hydroxyl radicals to produce the mixture. Illustrativeadditives can include, but are not limited to, waxes and/or otherhydrophobic additives, water, filler material(s), extenders,surfactants, release agents, dyes, fire retardants, formaldehydescavengers, biocides, any combination thereof, or any mixture thereof.For composite wood products, such as plywood, typical filler material(s)can include, but are not limited to, ground pecan and/or walnut shells,and typical extenders can include, for example, wheat flour. Othersuitable extenders can include, but are not limited to, polysaccharides,and the like. Illustrative polysaccharides can include, but are notlimited to, starch, cellulose, gums, such as guar and xanthan,alginates, pectin, gellan, any combination thereof, or any mixturethereof. Suitable polysaccharide starches can include, for example maizeor corn, waxy maize, high amylose maize, potato, tapioca, and wheatstarch. Other starches such as genetically engineered starches caninclude high amylose potato and potato amylopectin starches.

If one or more additives is present in the mixture, the amount of eachadditive can range from a low of about 0.01 wt % to a high of 50 wt %,based on the total weight of the mixture. For example, the amount of anygiven component or additive can range from a low of about 0.01 wt %,about 0.05 wt %, about 0.1 wt %, about 0.5 wt %, or about 1 wt % to ahigh of about 3 wt %, about 5 wt %, about 7 wt %, or about 9 wt %, basedon the total weight of the mixture. In another example, the amount ofany given additive or component can range from a low of about 1 wt %,about 5 wt %, about 10 wt %, about 15 wt %, or about 20 wt % to a highof about 25 wt %, about 30 wt %, about 35 wt %, about 40 wt %, or about45 wt %, based on the total weight of the mixture. In at least onespecific embodiment, one or more waxes, e.g., slack wax, can be presentin the mixture and the amount of wax can range from a low of about 0.1wt %, about 0.5 wt %, or about 0.9 wt % to a high of about 1.5 wt %,about 2 wt %, or about 3 wt %, based on the dry weight of thelignocellulose substrates.

The composite product can have a density from a low of about 0.5 g/cm³,about 0.55 g/cm³, about 0.6 g/cm³, about 0.63 g/cm³, about 0.65 g/cm³,about 0.67 g/cm³, or about 0.7 g/cm³ to a high of about 0.75 g/cm³,about 0.77 g/cm³, about 0.8 g/cm³, about 0.83 g/cm³, about 0.85 g/cm³,about 0.88 g/cm³, about 0.93 g/cm³, about 0.97 g/cm³, or about 1 g/cm³.For example, the composite product can have a density of about 0.7 g/cm³to about 0.75 g/cm³, about 0.65 g/cm³ to about 0.85 g/cm³, about 0.65g/cm³ to about 0.8 g/cm³, about 0.67 g/cm³ to about 0.77 g/cm³, about0.5 g/cm³, to about 1 g/cm³, about 0.5 g/cm³, to about 0.8 g/cm³, about0.5 g/cm³ to about 0.75 g/cm³, or about 0.64 g/cm³ to about 0.8 g/cm³.In one or more embodiments, the composite product can have density lessthan 1 g/cm³, less than 0.95 g/cm³, less than 0.88 g/cm³, less than 0.85g/cm³, less than 0.83 g/cm³, less than 0.8 g/cm³, less than 0.79 g/cm³,less than 0.78 g/cm³, less than 0.77 g/cm³, less than 0.76 g/cm³, lessthan 0.75 g/cm³, less than 0.74 g/cm³, or less than 0.73 g/cm³.

The composite product can have an internal bond strength from a low ofabout 0.3 MPa, about 0.32 MPa, about 0.34 MPa, about 0.35 MPa, about0.37 MPa, about 0.4 MPa, about 0.42 MPa, about 0.48 MPa, about 0.52 MPa,about 0.55 MPa, or about 0.58 MPa to a high of about 0.69 MPa, about0.75 MPa, about 0.83 MPa, about 0.9 MPa, about 0.97 MPa, about 1.05 MPa,about 1.15 MPa, about 1.2 MPa, about 1.25 MPa, about 1.3 MPa, about 1.35MPa, about 1.4 MPa, about 1.45 MPa, about 1.5 MPa, about 1.55 MPa, about1.6 MPa, or about 1.7 MPa, with suitable ranges including thecombination of any two values. For example, the composite product canhave an internal bond strength of about 0.35 MPa to about 0.55 MPa,about 0.4 MPa to about 0.6 MPa, about 0.48 MPa to about 0.69 MPa, about0.59 MPa to about 0.86 MPa, about 0.55 MPa to about 0.9 MPa, or about0.51 MPa to about 0.85 MPa. In one or more embodiments, the compositeproduct can have an internal bond strength of at least 0.33 MPa, atleast 0.32 MPa, at least 0.34 MPa, at least 0.38 MPa, at least 0.41 MPa,at least 0.45 MPa, at least 0.48 MPa, at least 0.51 MPa, at least 0.55MPa, at least 0.58 MPa, at least 0.62 MPa, at least 0.66 MPa, at least0.69 MPa, at least 0.72 MPa, at least 0.76 MPa, or at least 0.79 MPa.The internal bond strength for each example can be determined accordingto the test procedure provided for in ASTM D1037-06a.

In one or more embodiments, the composite product can have a densityless than 1 g/cm³, less than 0.95 g/cm³, less than 0.9 g/cm³, less than0.85 g/cm³, less than 0.8 g/cm³, less than 0.79 g/cm³, less than 0.78g/cm³, less than 0.77 g/cm³, less than 0.76 g/cm³, less than 0.75 g/cm³,less than 0.74 g/cm³, or less than 0.73 g/cm³ and an internal bondstrength of at least 0.3 MPa, at least 0.35 MPa, at least 0.4 MPa, atleast 0.48 MPa, at least 0.51 MPa, at least 0.55 MPa, at least 0.58 MPa,at least 0.62 MPa, at least 0.65 MPa, or at least 0.69 MPa. In at leastone specific example, the composite product can have a density less than0.8 g/cm³ and internal bond strength of at least 0.48 MPa. In at leastone other specific example, the composite product can have a densityless than 0.8 g/cm³ and internal bond strength of at least 0.69 MPa. Inat least one other specific example, the composite product can have adensity of less than 0.73 g/cm³ and internal bond strength of at least0.48 MPa. In still another example, the composite product can have adensity of less than 0.73 g/cm³ and internal bond strength of at least0.58 MPa.

Composite products such as particleboard, fiberboard, plywood, andoriented strand board, can have a thickness or average thickness from alow of about 1.5 mm, about 5 mm, or about 10 mm to a high of about 15mm, about 20 mm, about 25 mm, about 30 mm, about 50 mm, about 100 mm,about 200 mm, or about 300 mm, with suitable ranges including thecombination of any two values. Composite products such as particleboard,fiberboard, plywood, and oriented strand board can have a length ofabout 0.1 m, about 0.5 m, about 1 m, about 1.2 m, about 1.8 m, about 2.4m, about 3 m, or about 3.6 m. The composite products can also have awidth of about 0.1 m, about 0.5 m, about 1 m, about 1.2 m, about 1.8 m,about 2.4 m, or about 3 m.

The mixtures discussed and described herein can be free or essentiallyfree of formaldehyde for use in the production of the compositeproducts, e.g., wood products such as particleboard and plywood. As usedherein, the term “essentially free of formaldehyde” means the mixturedoes not include or contain any intentionally added formaldehyde orcompounds that can decompose, react, or otherwise form formaldehyde.Said another way, the term “essentially free of formaldehyde” means themixture does not contain formaldehyde or compounds that can formformaldehyde, but may include formaldehyde present as an impurity.Accordingly, depending on the particular multifunctional aldehyde(s)used to produce the mixtures discussed and described herein, the mixturecan be referred to as “no added formaldehyde” or “NAF” mixture.

The composite products discussed and described herein can exhibit a lowlevel of formaldehyde emission. A suitable test for determiningformaldehyde emission from a composite product can include ASTM D6007-02and AST E1333-10. For example, the composite products can exhibit aformaldehyde emission of zero. In another example, the compositeproducts can exhibit a formaldehyde emission of less than about 1 partper million (“ppm”), less than about 0.9 ppm, less than about 0.08 ppm,less than about 0.07 ppm, less than about 0.06 ppm, less than about 0.05ppm, less than about 0.04 ppm, less than about 0.03 ppm, less than about0.02 ppm, less than about 0.01 ppm, or less than about 0.005 ppm.

The composite product can meet or exceed the formaldehyde emissionstandards required by the California Air Resources Board (“CARB”) Phase1 (less than 0.1 parts per million “ppm” formaldehyde forparticleboard), and Phase 2 (less than 0.09 ppm formaldehyde forparticleboard). The composite products discussed and described hereincan also meet or exceed the formaldehyde emission standards required bythe Japanese JIS/JAS F*** (does not exceed 0.5 mg/L formaldehyde forparticleboard), Japanese JIS/JAS F**** (does not exceed 0.3 mg/Lformaldehyde for particleboard), European E1, and European E2 standards.

EXAMPLES

In order to provide a better understanding of the foregoing discussion,the following non-limiting examples are offered. Although the examplesmay be directed to specific embodiments, they are not to be viewed aslimiting the invention in any specific respect. All parts, proportions,and percentages are by weight unless otherwise indicated.

Example I

A series of catalysts were used to produce particleboard panels, namely,comparative examples C1 and C2 and inventive examples Ex. 1-7. For allexamples, 2,100 grams of face-grade wood particles (Southern YellowPine) was placed in 0.0283 m³ blender. The wood particles had a moisturecontent of 5 wt % to 7 wt %. To the wood furnish was added ammoniumlignosulfonate in both liquid form and powder form, an iron containingcatalyst, and 50 wt % hydrogen peroxide solution.

The additional components of the mixture were sprayed onto the woodparticles in the following order and amounts: (1) 7 wt % of ammoniumlignosulfonate (46 wt % to 49 wt % aqueous mixture) mixed with 0.1 wt %catalyst (which differed for each example); (2) 5 wt % of the hydrogenperoxide, and (3) 3 wt % of the powdered ammonium lignosulfonate, wherethe amount of each component is based on the dry weight of the woodparticles. The catalysts used in comparative examples C1 and C2 wereFeSO₄×7H₂O, and NH₄Fe(SO₄)₂×12H₂O, respectively. The catalyst used ininventive examples 1-7 were potassium ferricyanide (K₃[Fe(CN)₆]), ironethylenediaminetetraacetic acid (Fe EDTA), ironethylenediaminetetraacetic acid (Fe EDTA), iron(S,S)-ethylenediamine-N,N′-disuccinic acid (Fe EDDS), irondiethylenetriamine pentaacetic acid (Fe DTPA), iron ethyleneglycolbis(2-aminoethyleter)-N,N,N′,N′-tetraacetic acid (Fe EGTA), and irontrans-1,2-diaminocyclohexanetetraacetic acid (Fe CDTA), respectively.The aqueous ammonium lignosulfonate was ARBO®A02L provided by Tembec.The powdered ammonium lignosulfonate was ARBO®A02P provided by Tembec.

The FeSO₄×7H₂O and NH₄Fe(SO₄)₂×12H₂O were both purchased fromSigma-Aldrich and each had a purity of ≧99.0%. The (K₃[Fe(CN)₆]) waspurchased from J. T. Baker Chemical Co. and had a purity of 99.5%. TheFe EDTA was purchased from Acros Organic and had a purity of 98%. TheFeCl₃ was purchased from Sigma-Aldrich and had a purity of 97%. The EDDSwas purchased from Sigma-Aldrich as a 35% aq. trisodium salt solution.The DTPA was purchased from Sigma-Aldrich and had a purity of 98%. TheEGTA was purchased from Sigma-Aldrich as a tetrasodium salt and had apurity of 97.0%. The CDTA monohydrate was purchased from Fluka and had apurity of 98.5%. Iron chelates were made by mixing 1.0 equiv. of aqueoussolution of FeCl3 with 1.05 equiv. of aqueous solution of thecorresponding sodium salt of the chelate at room temperature. Sodiumsalts of DTPA and CDTA chelates were made by the addition of sodiumhydroxide to the corresponding chelate. Freshly prepared iron chelatesolutions were used in the experiments.

The mixture or “resinated furnish” had a total moisture content of 17 wt% to 18 wt % and was blended for an additional 2 minutes after addingthe powdered ammonium lignosulfonate. The resinated furnish was placedin a 33 cm×45.7 cm×20.3 cm open container for 30 minutes during whichtime the temperature of the resinated furnish was measured. For eachexample, the initial or starting temperature of the resinated furnishvaried due to one or more factors, which included the initialtemperature of the wood particles varying due how long the woodparticles were allowed to cool after drying, the ambient temperature onthe given day of the experiments which took place from January to July,and, as can be seen in Table 1, for the comparative examples C1 and C2the components of the furnish were highly reactive with one anothercompared to Ex. 1-7 and heat generated upon or shortly after formationof the mixture contributed to the differences in initial startingtemperatures. The temperature of each resinated furnish during the 30minutes is shown in Table 1 below.

TABLE 1 C1, Ex. 2, Ex. 3, Ex. 4, Ex. 5, Ex. 6, Ex. 7, FeSO₄ × C2, Fe FeFe Fe Fe Fe 7H₂O NH₄Fe(SO₄)₂ × Ex. 1, EDTA EDTA EDDS DTPA EGTA CDTATime, Temp, 12H₂O K₃[Fe(CN)₆] Temp, Temp, Temp, Temp, Temp, Temp, min. °C. Temp, ° C. Temp, ° C. ° C. ° C. ° C. ° C. ° C. ° C. 2 34.4 — 26.825.1 26.6 — — 36.4 29.1 3 — 34.3 — — 33.6 34.0 — — 4 36.3 — 27.7 25.726.8 — — 37.6 29.2 6 — 36.7 29.7 26.4 34.0 34.1 38.4 29.4 8 — — 29.7 —27.0 34.2 34.2 — — 9 — — — — — — — 29.6 10 — — — 26.4 27.1 34.5 — 40.4 —11 — — — — — — — 29.8 12 41.4 44.0 — 26.5 — — 41.5 — 13 — — — — 34.7 — —30.0 14 — — 28.7 26.6 — 34.7 42.8 — 15 — — — — 27.3 — — — 30.2 16 — —29.1 26.8 — — — — 18 47.9 64.0 — 26.9 27.4 — 34.9 — — 19 — — — 26.9 35.2— — 30.4 20 — — 29.4 26.9 27.5 — 35.0 47.7 — 21 — 90.6 — — — — — — 2256.8 104.0  — — — 35.1 — — 23 — — — — — — — 30.6 24 65.7 104.0  29.7 —35.4 35.1 — — 25 — 104.0  — — — — 51.5 — 26 83.8 — — — 35.5 35.0 — — 2798.2 102.0  — — — — — — 28 105.1  — 30.0 — 27.9 35.5 — 54.8 — 30 106.8 98.4 30.1 — 28.0 35.6 35.0 57.4 30.8

As shown in Table 1, the resinated furnish of comparative examples C1and C2 all exceeded a temperature of 40° C. in less than 30 minutes. Infact, all of the comparative examples C1 and C2 exceeded 100° C. Indirect contrast, none of the inventive examples Ex. 1-7 exceeded atemperature of 60° C. over the 30 minute duration.

After the 30 minutes in the a 33 cm×45.7 cm×20.3 cm open container, theresinated furnish was formed into a 40.64 cm×40.64 cm×5.08 cm mat and aparticleboard panel was pressed to stops configured to produce a panelhaving a thickness of 1.59 cm+/−0.3 cm for 4 minutes at 165.5° C.+/−5.5°C. (total press time of 240 seconds consisted of 30 seconds closingtime, 180 seconds press time, and 30 seconds degas time). Theparticleboard samples were then cooled to room temperature and internalbond (IB) strength was tested according to ASTM D1037-06a. Eachparticleboard panel had a thickness of 1.59 cm+/−0.3 cm. Theparticleboard density and internal bond strength for each sample areshown in Table 2 below.

TABLE 2 Example Catalyst Density, g/cm³ IB, MPA C1 FeSO₄ × 7H₂O 0.7740.49 C2 NH₄Fe(SO4)₂ × 12H₂O 0.770 0.185 Ex. 1 K₃[Fe(CN)₆] 0.803 0.772Ex. 2 Fe EDTA 0.745 0.591 Ex. 3 Fe EDTA 0.748 0.607 Ex. 4 Fe EDDS 0.7420.458 Ex. 5 Fe DTPA 0.769 0.403 Ex. 6 Fe EGTA 0.798 0.556 Ex. 7 Fe CDTA0.775 0.383

As shown in Table 2, all inventive examples Ex. 1-7 had an IB strengthof 0.383 MPa or more. Comparative example C2 had a significantly lowerIB strength of 0.185 MPa. Comparative example C1 had a comparable IBstrength of 0.490 MPa, but the resinated furnish exceeded 100° C. within30 minutes. When the resinated furnish exceeds 100° C. a substantialamount of heat and steam can be generated, which in addition to beingundesirable from a manufacturing standpoint, also presents a safetyhazard to people involved in the manufacturing of composite products.Particleboard panels having an IB of about 0.350 MPa or more are usefulfor numerous applications, which include, but are not limited to,furniture, cabinetry, flooring, and wall units.

Example II

In Example II four examples were prepared, namely, a Control, andinventive examples Ex. 8-10 and the amount of oxidant (hydrogenperoxide) that remained present in each example after 30 minutes wasdetermined. Face-grade wood particles (Southern Yellow Pine) in theamount of 2,100 g was placed in 0.0283 m³ blender. The wood particleshad a moisture content of 5 wt % to 7 wt %. The Control example includedonly hydrogen peroxide, i.e., no catalyst, wood particles, or ammoniumlignosulfonate were present. For Example 8, the following componentswere added to the wood particles in the form a fine mist while blendingto produce the resinated furnish: a) 7 wt % of ammonium lignosulfonate(46 wt % to 49 wt % aqueous mixture), b) 5 wt % of hydrogen peroxide(50% aq.), and c) 3 wt % of powdered ammonium lignosulfonate, where theamount of each component was based on the dry weight of the woodparticles. For Examples 9 and 10, the following components were added tothe wood particles while blending to produce the resinated furnish: a) 7wt % of ammonium lignosulfonate (46 wt % to 49 wt % aqueous mixture)mixed with 0.275 wt % FeEDTA (Ex. 9) and 0.22 wt % K₃[Fe(CN)₆] (Ex. 10),respectively, b) 5 wt % of hydrogen peroxide (50% aq.), and c) 3 wt % ofpowdered ammonium lignosulfonate, where the amount of each component wasbased on the dry weight of the wood particles.

The resinated furnishes of Examples 8-10 (moisture content 17-18%) wereblended for an additional 2 min and then placed in a 33 cm×45.7 cm×20 cmopen container for 30 min during which time the temperature of theresinated furnish was measured. A representative sample of eachresinated wood furnish in the amount of 20 g was transferred to plasticcontainer and 200 g of deionized water was added. For the controlsample, 0.95 g of the H₂O₂ was transferred to a plastic container and400 g of deionized water was added thereto. The H₂O₂ content was thenanalyzed using triphenylphosphine, as further discussed below. ForExamples 8-10, the mixtures were hand stirred for 5 min and poured intoa funnel equipped with filter paper. For Examples 8 and 10, thefiltrates were collected and the wood furnish was rinsed two more timeswith an additional 800 g of deionized water (2 separate rinses of 400 geach). For Example 9, the filtrate was collected and the wood furnishwas rinsed one additional time with 400 g of deionized water.

For Examples 8-10, the rinsed filtrates were diluted by adding 1 mL offiltrate to a 100 mL volumetric flask and the remainder of the flask wasfilled with water. A 2.0 mM solution of triphenylphosphine inacetonitrile was then prepared. 1 mL of each solution was mixed togetherin a plastic container and stored in the dark for 30 minutes duringwhich time the triphenylphosphine oxidized to triphenylphosphine oxide.The triphenylphosphine oxide concentration was measured by HPLC. Thetriphenylphosphine and triphenylphosphine oxide (used for calibrationcurve) were purchased from Aldrich and had a purity of 99% and 98%,respectively. The analytical procedure using the triphenylphosphine inacetonitrile to determine the hydrogen peroxide content was conductedaccording to the procedure discussed and described in Pinkernell, U.;Effkemann, S.; Karst, U., Anal. Chem. 1997, 69, 3623-3627.

The results are shown in Table 3 below.

TABLE 3 Components % H₂O₂ retained Control H₂O₂ 98 Ex. 8 ALS + H₂O₂ 81Ex. 9 ALS + FeEDTA + H₂O₂ 63 Ex. 10 ALS + K₃[Fe(CN)₆] + H₂O₂ 83

As shown in Table 3, the control example only lost 2% of the hydrogenperoxide, which should be due to experimental error and/or decompositionof the hydrogen peroxide caused by light during the 30 minute monitoringstep. Examples 8-10 each had a hydrogen peroxide concentration of 81%,63%, and 83%, respectively, that remained present after the minutemonitoring step. Without wishing to be bound by theory, it is believedthat Ex. 9 showed a greater decrease in the H₂O₂ content due to rinsingthe mixture only once, which most likely was insufficient to recover theadditional H₂O₂. Also, without wishing to be bound by theory it isbelieved that the H₂O₂ not recovered could be due to decomposition ofhydrogen peroxide, there may be an equilibrium between the H₂O₂ and thefurnish, and/or the H₂O₂ may react with some components of the wood thatcan be oxidized by just H₂O₂.

Embodiments of the present disclosure further relate to any one or moreof the following paragraphs:

1. A method for making a composite product, comprising: combining aplurality of lignocellulose substrates and one or more free radicalprecursors to produce a mixture; maintaining the mixture at atemperature less than 60° C. for at least 10 minutes; and heating themixture to a temperature of at least 60° C. to about 300° C. to producea composite product having a density less than 1 g/cm³ and an internalbond strength of at least 0.35 MPa, wherein at least 1 wt % of the oneor more free radical precursors is present when the mixture is heated toat least 60° C., based on a dry weight of the plurality oflignocellulose substrates.

2. A method for making a composite product, comprising: combining aplurality of lignocellulose substrates and one or more free radicalprecursors to produce a mixture; maintaining the mixture at atemperature less than 60° C. for at least 10 minutes; and heating themixture to a temperature of at least 60° C. to about 300° C. to producea composite product having a density less than 1 g/cm³ and an internalbond strength of at least 0.35 MPa, wherein at least 11 wt % of the oneor more free radical precursors is present when the mixture is heated toat least 60° C.

3. A method for making a composite product, comprising: combining aplurality of lignocellulose substrates, one or more free radicalprecursors, and one or more compounds selected from the group consistingof: lignins, tannins, novolac resins, modified phenol formaldehyderesin, bis-phenol A, humic acids, and any mixture thereof to produce amixture; and heating the mixture to a temperature of about 60° C. toabout 300° C. to produce a composite product, wherein at least 11 wt %of the one or more free radical precursors is present when the mixtureis heated to at least 60° C.

4. The method according to paragraph 3, wherein the composite producehas a density less than 1 g/cm³ and an internal bond strength of atleast 0.35 MPa.

5. The method according to paragraph 4, wherein an amount of the one ormore free radical precursors present when the mixture is heated to about60° C. to about 300° C. is at least 1 wt %, based on a dry weight of theplurality of lignocellulose substrates.

6. A method for making a composite product, comprising: combining aplurality of lignocellulose substrates, one or more free radicalprecursors, and one or more compounds comprising at least two hydrogenatoms that are abstractable in the presence of hydroxyl radicals toproduce a mixture; and heating the mixture to a temperature of about 60°C. to about 300° C. to produce a composite product, wherein at least 11wt % of the one or more free radical precursors is present when themixture is heated to about 60° C. to about 300° C.

7. The method according to paragraph 6, wherein the composite producthas a density less than 1 g/cm³ and an internal bond strength of atleast 0.35 MPa.

8. The method according to paragraph 6, wherein an amount of the one ormore free radical precursors present when the mixture is heated to about60° C. is at least 1 wt %, based on a dry weight of the plurality oflignocellulose substrates.

9. A method for preparing a composite product, comprising: combining aplurality of lignocellulose substrates, one or more oxidants, and one ormore catalysts to produce a mixture, wherein the one or more catalystscomprises a plurality of transition metal atoms each bound to acorresponding complexing agent; and heating the mixture to a temperatureof about 60° C. to about 300° C. to produce a composite product having adensity less than 1 g/cm³ and an internal bond strength of at least 0.35MPa, wherein at least 1 wt % of the one or more catalysts comprising theplurality of transition metal atoms each bound to the correspondingcomplexing agent is present when the mixture is heated to about 60° C.to about 300° C., based on a dry weight of the plurality oflignocellulose substrates.

10. The method according to any one of paragraphs 1 to 8, wherein theone or more free radical precursors comprises a mixture of one or moreoxidants and one or more catalysts.

11. The method according to any one of paragraphs 1 to 8 or 10, whereinthe one or more free radical precursors comprises a mixture of hydrogenperoxide and one or more iron containing catalysts.

12. The method according to any one of paragraphs 1 to 8, 10, or 11,wherein the one or more free radical precursors generate radicals whenheated to a temperature from about 60° C. to about 300° C.

13. The method according to any one of paragraphs 1 to 5 or 9, furthercomprising combining one or more compounds comprising at least twohydrogen atoms that are abstractable in the presence of hydroxylradicals.

14. The method according to paragraph 13, wherein the one or morecompounds comprising at least two hydrogen atoms that are abstractablein the presence of hydroxyl radicals comprises lignin, tannins, novolac,bis-phenol A, modified phenol formaldehyde resin, humic acids or anymixture thereof.

15. The method according to paragraph 14, wherein the lignin is presentand comprises ammonium lignosulfonate, sodium lignosulfonate, or amixture thereof.

16. The method according to any one of paragraphs 1 to 15, furthercomprising pressing the mixture to a pressure greater than atmosphericpressure when the mixture is heated.

17. The method according to any one of paragraphs 1 to 16, furthercomprising pressing the mixture to a pressure of about 0.1 MPa to about10 MPa when the mixture is heated.

18. The method according to any one of paragraphs 1 to 17, wherein thecomposite product is in the form of a panel having an average thickness,and wherein the mixture is heated for about 3 seconds to about 20seconds per millimeter of the average thickness.

19. The method according to any one of paragraphs 1 to 18, wherein thecomposite product is in the form of a panel having an average thickness,and wherein the mixture is heated for about 10 seconds to about 18seconds per millimeter of the average thickness.

20. The method according to paragraph 1 or 2, wherein the mixture ismaintained at the temperature less than 60° C. for at least 15 minutes.

21. The method according to paragraph 1 or 2, wherein the mixture ismaintained at the temperature less than 60° C. for at least 20 minutes.

22. The method according to paragraph 1 or 2, wherein the mixture ismaintained at the temperature less than 60° C. for at least 25 minutes.

23. The method according to paragraph 1 or 2, wherein the mixture ismaintained at the temperature less than 60° C. for at least 30 minutes.

24. The method according to any one of paragraphs 1 to 23, wherein thecomposite product has an internal bond strength of at least 0.4 MPa.

25. The method according to any one of paragraphs 1 to 24, wherein thecomposite product has a density from about 0.5 g/cm³ to less than 1g/cm³.

26. The method according to any one of paragraphs 1 to 25, wherein thecomposite product has an internal bond strength of at least 0.5 MPa anda density of less than 0.9 g/cm³.

27. The method according to any one of paragraphs 1 to 26, wherein thecomposite product has a density from about 0.5 g/cm³ to about 0.85g/cm³.

28. The method according to any one of paragraphs 1 to 27, wherein thecomposite product has an internal bond strength of at least 0.5 MPa anda density of less than 0.8 g/cm³.

29. The method according to any one of paragraphs 1 to 8, wherein theone or more free radical precursors comprises one or more catalysts, andwherein the one or more catalysts comprises one or more metals in theform of a complex bound to one or more complexing agents.

30. The method according to paragraph 29, wherein the one or morecatalysts comprises one or more metals.

31. The method according to paragraph 30, wherein the one or morecomplexing agents comprises cyanide (CN), sulfate (SO₄ ²⁻),ethylenediaminetetraacetic acid (EDTA), ethylenediamine-N,N′-disuccinicacid (EDDS), ethyleneglycol bis(2-aminoethyl ter)-N,N,N′,N′-tetraaceticacid (EGTA), diethylenetriaminepentaacetic acid (DTPA),trans-1,2-diaminocyclohexane tetraacetic acid (CDTA), iminodisuccinate(IDS), nitrilotracetic acid (NTA), or any mixture thereof.

32. The method according to paragraph 30 or 31, wherein the one or moremetals comprises iron, copper, manganese, tungsten, molybdenum, cobalt,titanium, or any mixture thereof.

33. The method according to any one of paragraphs 9 or 30 to 32, whereinthe one or more catalysts comprises one or more metal ions of iron,copper, manganese, tungsten, molybdenum, cobalt, titanium, or anycombination thereof; one or more tertiary amines; polymeric tertiaryamines; polyamines, or a combination thereof.

34. The method according to paragraph 9, wherein the one or morecatalysts is selected from the group consisting of: potassiumferricyanide, iron ethylenediaminetetraacetic acid, iron(S,S)-ethylenediamine-N,N′-disuccinic acid, iron diethylenetriaminepentaacetic acid, iron ethlyleneglycolbis(2-aminoethyleter)-N,N,N′,N′-tetraacetic acid, irontrans-1,2-diaminocyclohexanetetraacetic acid, and any mixture thereof.

35. The method according to paragraph 9 or 30, wherein an amount of theone or more catalysts present in the mixture is from about 0.05 wt % toabout 5 wt %, based on a dry weight of the plurality of lignocellulosesubstrates.

36. The method according to paragraph 9, further comprising combiningone or more polyphenolic compounds with the plurality of lignocellulosesubstrates, the one or more oxidants, and the one or more catalysts toproduce the mixture.

37. The method according to paragraph 36, wherein the one or morepolyphenolic compounds is selected from the group consisting of: lignin,tannins, a novolac resin, modified phenol formaldehyde resin, humicacids, or any combination thereof.

38. The method according to paragraph 37, wherein the lignin is presentand comprises ammonium lignosulfonate.

39. The method according to any one of paragraphs 36 to 38, wherein theone or more polyphenolic compounds is present in the mixture in anamount of about 1 wt % to about 30 wt %, based on a dry weight of theplurality of lignocellulose substrates.

40. The method according to any one of paragraphs 36 to 39, wherein thepolyphenolic compound is modified with one or more compounds havingcarbon-carbon double bonds and one or more functional groups.

41. The method according to paragraph 40, wherein the one or morecompounds having carbon-carbon double bonds and one or more functionalgroups is selected from the group consisting of: an unsaturated glycidylether, an unsaturated glycidyl ester, an unsaturated mono-epoxide, anunsaturated methylol compound, maleic anhydride, or any mixture thereof.

42. The method according to paragraph 40 or 41, wherein the polyphenoliccompound modified with the one or more compounds having carbon-carbondouble bonds and one or more functional groups is present in an amountof about 2 wt % to about 30 wt %, based on a dry weight of the pluralityof lignocellulose substrates.

43. The method according to any one of paragraphs 1 to 8 or 10 to 42,wherein the one or more free radical precursors is present in themixture in an amount of about 1 wt % to about 15 wt %, based on a dryweight of the plurality of lignocellulose substrates.

44. The method according to paragraph 43, wherein the one or more freeradical precursors comprises hydrogen peroxide.

45. The method according to paragraph 9, wherein the one or moreoxidants comprises one or more inorganic peroxy compounds, one or moreorganic peroxy compounds, or a combination thereof.

46. The method according to paragraph 9, wherein the one or moreoxidants comprises hydrogen peroxide.

47. The method according to paragraph 9, wherein an amount of the one ormore oxidants present in the mixture is from about 1 wt % to about 15 wt%, based on a dry weight of the plurality of lignocellulose substrates,and wherein an amount of the one or more catalysts present in themixture is from about 0.05 wt % to about 5 wt %, based on the dry weightof the plurality of lignocellulose substrates.

48. The method according to any one of paragraphs 1 to 47, wherein thecomposite product comprises a particleboard, a fiberboard, a plywood, anoriented strand board, a laminated veneer lumber, or a laminated veneerboard.

49. The method according to paragraph 9, wherein at least 15 wt % of theoxidant is present when the mixture is heated to at least 60° C.

50. The method according to paragraph 9, wherein at least 20 wt % of theoxidant is present when the mixture is heated to at least 60° C.

51. The method according to paragraph 9, wherein at least 50 wt % of theoxidant is present when the mixture is heated to at least 60° C.

52. A composite product, comprising: an at least partially curedcomposition having a density less than 1 g/cm³ and an internal bondstrength of at least 0.35 MPa, wherein the at least partially curedcomposition, prior to curing, comprises a plurality of lignocellulosesubstrates, one or more free radical precursors, and one or morecompounds selected from the group consisting of: lignins, tannins,novolac resins, bis-phenol A, modified phenol formaldehyde resin, humicacids, and any mixture thereof.

53. A composite product, comprising: an at least partially curedcomposition having a density less than 1 g/cm³ and an internal bondstrength of at least 0.35 MPa, wherein the composition, prior to curing,comprises a plurality of lignocellulose substrates, one or more freeradical precursors, and one or more compounds comprising at least twohydrogen atoms that are abstractable in the presence of hydroxylradicals.

54. A composite product comprising a mixture that has been heated to atemperature from about 60° C. to about 300° C., wherein the mixture,prior to being heated, comprises a plurality of lignocellulosesubstrates, one or more free radical precursors, and one or morecompounds selected from the group consisting of: lignins, tannins,novolac resins, bis-phenol A, modified phenol formaldehyde resin, humicacids, and any mixture thereof, and wherein the heated mixture has aninternal bond strength of at least 0.35 MPa and a density less than 1g/cm³.

55. A composite product comprising a mixture that has been heated to atemperature from about 60° C. to about 300° C., wherein the mixture,prior to being heated, comprises a plurality of lignocellulosesubstrates, one or more free radical precursors, and one or morecompounds comprising at least two hydrogen atoms that are abstractablein the presence of hydroxyl radicals, and wherein the heated mixture hasan internal bond strength of at least 0.35 MPa and a density less than 1g/cm³.

56. A composite product having an internal bond strength of at least0.35 MPa and a density less than 1 g/cm³, wherein the composite productcomprises a cured mixture of a plurality of lignocellulose substrates,one or more free radical precursors, and one or more compounds selectedfrom the group consisting of: lignins, tannins, novolac resins,bis-phenol A, modified phenol formaldehyde resin, humic acids, and anymixture thereof.

57. A composite product having an internal bond strength of at least0.35 MPa and a density less than 1 g/cm³, wherein the composite productcomprises a cured mixture of a plurality of lignocellulose substrates,one or more free radical precursors, and one or more compoundscomprising at least two hydrogen atoms that are abstractable in thepresence of hydroxyl radicals.

58. A composite product having an internal bond strength of at least0.35 MPa and a density less than 1 g/cm³, wherein the composite productcomprises a mixture that has been heated to a temperature from about 60°C. to about 300° C., and wherein prior to heating the mixture comprisesa plurality of lignocellulose substrates, one or more free radicalprecursors, and one or more compounds selected from the group consistingof: lignins, tannins, novolac resins, bis-phenol A, modified phenolformaldehyde resin, humic acids, and any mixture thereof.

59. A composite product having an internal bond strength of at least0.35 MPa and a density less than 1 g/cm³, wherein the composite productcomprises a mixture that has been heated to a temperature from about 60°C. to about 300° C., and wherein prior to heating the mixture comprisesa plurality of lignocellulose substrates, one or more free radicalprecursors, and one or more compounds comprising at least two hydrogenatoms that are abstractable in the presence of hydroxyl radicals.

60. The composite product according to any one of paragraphs 52 to 59,wherein the internal bond strength of the composite product is at least0.4 MPa.

61. The composite product according to any one of paragraphs 52 to 59,wherein the internal bond strength of the composite product is at least0.45 MPa.

62. The composite product according to any one of paragraphs 52 to 59,wherein the internal bond strength of the composite product is at least0.5 MPa.

63. The composite product according to any one of paragraphs 52 to 59,wherein the composite product has an internal bond strength of at least0.4 MPa and a density of less than 0.9 g/cm³.

64. The composite product according to any one of paragraphs 52 to 59,wherein the composite product has an internal bond strength of at least0.4 MPa and a density of less than 0.85 g/cm³.

65. The composite product according to any one of paragraphs 52 to 59,wherein the composite product has an internal bond strength of at least0.4 MPa and a density of less than 0.8 g/cm³.

66. The composite product according to any one of paragraphs 52 to 59,wherein the composite product has an internal bond strength of at least0.4 MPa and a density of less than 0.75 g/cm³.

67. The composite product according to any one of paragraphs 52 to 59,wherein the composite product has an internal bond strength of at least0.5 MPa and a density of less than 0.9 g/cm³.

68. The composite product according to any one of paragraphs 52 to 59,wherein the density of the composite product is less than about 0.9g/cm³.

69. The composite product according to any one of paragraphs 52 to 59,wherein the density of the composite product is less than about 0.85g/cm³.

70. The composite product according to any one of paragraphs 52 to 59,wherein the density of the composite product is less than about 0.8g/cm³.

71. The composite product according to any one of paragraphs 52 to 59,wherein the density of the composite product is less than about 0.75g/cm³.

72. The composite product according to any one of paragraphs 52 to 59,wherein the one or more free radical precursors comprises one or moreoxidants.

73. The composite product according to any one of paragraphs 52 to 59,wherein the one or more free radical precursors comprises one or moreoxidants, and wherein the one or more oxidants comprises one or moreinorganic peroxy compounds, one or more organic peroxy compounds, or acombination thereof.

74. The composite product according to any one of paragraphs 52 to 59,wherein the one or more free radical precursors comprises one or moreoxidants, and wherein the one or more oxidants comprises hydrogenperoxide.

75. The composite product according to any one of paragraphs 52 to 59,wherein the one or more free radical precursors comprises one or moreoxidants and one or more catalysts.

76. The composite product according to paragraph 75, wherein the one ormore catalysts comprises one or more metals in the form of a complexbound to one or more complexing agents.

77. The composite product according to paragraph 76, wherein the one ormore complexing agents comprises cyanide (CN), sulfate (SO₄ ²⁻),ethylenediaminetetraacetic acid (EDTA), ethylenediamine-N,N′-disuccinicacid (EDDS), ethyleneglycol bis(2-aminoethyl ter)-N,N,N′,N′-tetraaceticacid (EGTA), diethylenetriaminepentaacetic acid (DTPA),trans-1,2-diaminocyclohexane tetraacetic acid (CDTA), iminodisuccinate(IDS), nitrilotracetic acid (NTA), or any mixture thereof.

78. The composite product according to paragraph 76 or 77, wherein theone or more metals comprises iron, copper, manganese, tungsten,molybdenum, cobalt, titanium, or any mixture thereof.

79. The composite product according to paragraph 75, wherein the one ormore catalysts comprises one or more metal ions of iron, copper,manganese, tungsten, molybdenum, cobalt, titanium, or any combinationthereof; one or more tertiary amines; polymeric tertiary amines;polyamines; any mixture thereof; or any combination thereof.

80. The composite product according to paragraph 75, wherein the one ormore catalysts is selected from the group consisting of: potassiumferricyanide, iron ethylenediaminetetraacetic acid, iron(S,S)-ethylenediamine-N,N′-disuccinic acid, iron diethylenetriaminepentaacetic acid, iron ethlyleneglycolbis(2-aminoethyleter)-N,N,N′,N′-tetraacetic acid, irontrans-1,2-diaminocyclohexanetetraacetic acid, and any mixture thereof.

81. The composite product according to any one of paragraphs 52 to 80,wherein the composite product is particleboard.

82. The composite product according to paragraph 81, wherein theparticleboard is grade M-3i as defined by ANSI A208.1-2009Particleboard.

83. The composite product according to paragraph 81, wherein theparticleboard is grade M-2 as defined by ANSI A208.1-2009 Particleboard.

84. The composite product according to paragraph 81, wherein theparticleboard is grade M-S as defined by ANSI A208.1-2009 Particleboard.

85. The composite product according to paragraph 81, wherein theparticleboard is grade M-1 as defined by ANSI A208.1-2009 Particleboard.

86. The composite product according to paragraph 81, wherein theparticleboard is grade M-0 as defined by ANSI A208.1-2009 Particleboard.

87. The composite product according to paragraph 81, wherein theparticleboard is grade H-3 as defined by ANSI A208.1-2009 Particleboard.

88. The composite product according to paragraph 81, wherein theparticleboard is grade H-2 as defined by ANSI A208.1-2009 Particleboard.

89. The composite product according to paragraph 81, wherein theparticleboard is grade H-1 as defined by ANSI A208.1-2009 Particleboard.

90. The composite product according to paragraph 81, wherein theparticleboard is particleboard flooring and is grade M-3 as defined byANSI A208.1-2009 Particleboard.

91. The composite product according to paragraph 81, wherein theparticleboard is particleboard flooring and is grade D-3 as defined byANSI A208.1-2009 Particleboard.

92. The composite product according to paragraph 81, wherein theparticleboard is particleboard flooring and is grade D-2 as defined byANSI A208.1-2009 Particleboard.

93. The composite product according to paragraph 81, wherein theparticleboard is particleboard flooring and is grade PBU as defined byANSI A208.1-2009 Particleboard.

94. A method for preparing a composite product, comprising: combining aplurality of lignocellulose substrates, one or more oxidants, and one ormore catalysts to produce a mixture, wherein the one or more catalystsis selected from the group consisting of: potassium ferricyanide, iron(S,S)-ethylenediamine-N,N′-disuccinic acid, iron ethlyleneglycolbis(2-aminoethyleter)-N,N,N′,N′-tetraacetic acid, irontrans-1,2-diaminocyclohexanetetraacetic acid, nitrilotracetic acid(NTA), and any mixture thereof; and heating the mixture to a temperatureof about 60° C. to about 230° C. to produce a composite product.

95. The method according to paragraph 94, wherein at least 11 wt % ofthe oxidant is present when the mixture is heated to at least 60° C.

96. The method according to paragraph 95, further comprising maintainingthe mixture at a temperature less than 60° C. for at least 10 minutesbefore the mixture is heated to the temperature of at least 60° C. toabout 230° C. to produce the composite product.

97. The method according to any one of paragraphs 94 to 96, wherein thecomposite product has an internal bond strength of at least 0.35 MPa.

98. The method according to any one of paragraphs 94 to 97, wherein thecomposite product has a density from about 0.5 g/cm³ to about 1 g/cm³.

99. The method according to any one of paragraphs 94 to 98, wherein thecomposite product has an internal bond strength of at least 0.35 MPa anda density of less than 1 g/cm³.

100. The method according to any one of paragraphs 94 to 99, furthercomprising combining one or more polyphenolic compounds with theplurality of lignocellulose substrates, the one or more oxidants, andthe one or more catalysts to produce the mixture.

101. The method according to paragraph 100, wherein the one or morepolyphenolic compounds is selected from the group consisting of: lignin,tannins, novolac resin, or any combination thereof.

102. The method according to paragraph 101, wherein the lignin ispresent and comprises ammonium lignosulfonate.

103. The method according to any one of paragraphs 94 to 102, whereinthe one or more oxidants comprises one or more inorganic peroxycompounds, one or more organic peroxy compounds, or a combinationthereof.

104. The method according to paragraph 103, wherein the one or moreoxidants comprises hydrogen peroxide.

105. The method according to any one of paragraphs 94 to 104, whereinthe one or more oxidants is present in an amount from about 1 wt % toabout 15 wt %, based on a dry weight of the lignocellulose substrates.

106. The method according to any one of paragraphs 94 to 105, whereinthe composite product comprises a particleboard, a fiberboard, aplywood, an oriented strand board, a laminated veneer lumber, or alaminated veneer board.

107. The method according to paragraph 94, wherein at least 15 wt % ofthe oxidant is present when the mixture is heated to at least 60° C.

108. The method according to paragraph 93, wherein at least 20 wt % ofthe oxidant is present when the mixture is heated to at least 60° C.

109. The method according to paragraph 94, wherein at least 50 wt % ofthe oxidant is present when the mixture is heated to at least 60° C.

110. The method according to paragraph 1 or 2, wherein an amount ofenergy generated from the mixture due to exothermic reaction(s) betweenthe components of the mixture is less than about 20 cal/g.

111. The method according to any one of paragraphs 3, 6, 9, or 95,wherein prior to heating the mixture to a temperature of about or atleast 60° C., an amount of energy generated from the mixture due toexothermic reaction(s) between the components of the mixture is lessthan about 20 cal/g.

112. The method according to any one of paragraphs 1, 2, 3, or 6,wherein the free radical precursor comprises a compound having thegeneral formula R—N═N—R′, wherein R and R′ is independently asubstituted aryl or a substituted alkyl.

113. The method according to any one of paragraphs 1, 2, 3, or 6,wherein the one or more free radical precursors comprisesazobisisobutyronitrile (AIBN).

114. A method for preparing a composite product, comprising: combining aplurality of lignocellulose substrates, one or more oxidants, and one ormore catalysts to produce a mixture, wherein the one or more catalystscomprises a transition metal atom bound to a complexing agent; andheating the mixture to a temperature of about 60° C. to about 300° C. toproduce a composite product having a density less than 1 g/cm³ and aninternal bond strength of at least 0.35 MPa, wherein at least 1 wt % ofthe one or more catalysts comprising the plurality of transition metalatoms each bound to the corresponding complexing agent is present whenthe mixture is heated to about 60° C. to about 300° C., based on a dryweight of the plurality of lignocellulose substrates.

115. A method for making a composite product, comprising: combining aplurality of lignocellulose substrates and one or more free radicalprecursors to produce a mixture; maintaining the mixture at atemperature less than 60° C. for at least 10 minutes; and heating themixture to a temperature of at least 60° C. to about 300° C. to producea composite product, wherein an amount of the one or more free radicalprecursors present when the mixture is heated to at least 60° C. is atleast 11 wt % of the one or more free radical precursors combined withthe plurality of lignocellulose substrates, and wherein the compositeproduct has a density less than 1 g/cm³ and an internal bond strength ofat least 0.35 MPa.

116. A method for making a composite product, comprising: combining aplurality of lignocellulose substrates, one or more free radicalprecursors, and one or more compounds comprising at least two hydrogenatoms that are abstractable in the presence of hydroxyl radicals toproduce a mixture; and heating the mixture to a temperature of at least60° C. to about 300° C. to produce a composite product, wherein anamount of the one or more free radical precursors present when themixture is heated to at least 60° C. is at least 11 wt % of the one ormore free radical precursors combined with the plurality oflignocellulose substrates and the one or more compounds comprising atleast two hydrogen atoms that are abstractable in the presence ofhydroxyl radicals.

117. The method according to paragraph 115, wherein the mixture ismaintained at the temperature less than 60° C. for at least 20 minutes,and wherein the amount of the one or more free radical precursorspresent when the mixture is heated to at least 60° C. is at least 25 wt% of the one or more free radical precursors combined with the pluralityof lignocellulose substrates.

118. The method according to paragraph 115, wherein the mixture ismaintained at the temperature less than 60° C. for at least 30 minutes.

119. The method according to any one of paragraphs 115 to 118, whereinthe composite product is in the form of a panel having an averagethickness, and wherein the mixture is heated to the temperature of atleast 60° C. to about 300° C. for about 3 seconds to about 20 secondsper millimeter of the average thickness.

120. The method according to any one of paragraphs 115 to 119, whereinprior to heating the mixture to the temperature of at least 60° C. toabout 300° C. to produce the composite product, an amount of energygenerated from the mixture due to any exothermic reaction is less than20 cal/g.

121. The method according to any one of paragraphs 115 to 120, whereinthe composite product has an internal bond strength of at least 0.5 MPaand a density of less than 0.9 g/cm³.

122. The method according to any one of paragraphs 115 to 121, whereinthe one or more free radical precursors comprise a mixture of one ormore oxidants and one or more catalysts.

123. The method according to paragraph 122, wherein the one or more freeradical precursors comprises a mixture of hydrogen peroxide and one ormore iron containing catalysts.

124. The method according to paragraph 123, wherein an amount of the oneor more iron containing catalysts present in the mixture is from about0.05 wt % to about 5 wt %, based on a dry weight of the plurality oflignocellulose substrates.

125. The according to any one of paragraphs 115 to 124, wherein the oneor more free radical precursors comprise one or more catalysts, andwherein the one or more catalysts comprise one or more metals in theform of a complex bound to one or more complexing agents.

126. The method according to paragraph 125, wherein the one or morecomplexing agents comprise cyanide (CN), sulfate (SO₄ ²),ethylenediaminetetraacetic acid (EDTA), ethylenediamine-N,N′-disuccinicacid (EDDS), ethyleneglycol bis(2-aminoethyl ter)-N,N,N′,N′-tetraaceticacid (EGTA), diethylenetriaminepentaacetic acid (DTPA),trans-1,2-diaminocyclohexane tetraacetic acid (CDTA), iminodisuccinate(IDS), nitrilotracetic acid (NTA), or any mixture thereof.

127. The method according to any one of paragraphs 115 to 126, whereinthe one or more free radical precursors comprise one or more catalystsand one or more oxidants, and wherein the one or more catalysts comprisepotassium ferricyanide, iron ethylenediaminetetraacetic acid, iron(S,S)-ethylenediamine-N,N′-disuccinic acid, iron diethylenetriaminepentaacetic acid, iron ethlyleneglycolbis(2-aminoethyleter)-N,N,N′,N′-tetraacetic acid, irontrans-1,2-diaminocyclohexanetetraacetic acid, or any mixture thereof.

128. The method according to any one of paragraphs 115 to 127, whereinthe one or more free radical precursors comprise hydrogen peroxide.

129. The method according to any one of paragraphs 115 or 117 to 128,further comprising combining one or more polyphenolic compounds with theplurality of lignocellulose substrates and the one or more free radicalprecursors to produce the mixture, wherein the one or more polyphenoliccompounds comprise lignin, tannins, a novolac resin, modified phenolformaldehyde resin, bis-phenol A, humic acids, or any mixture thereof.

130. The method according to any one of paragraphs 116 to 130, whereinthe mixture is maintained at a temperature less than 60° C. for at least10 minutes prior to heating the mixture to the temperature of at least60° C. to about 300° C., and wherein the composite product has a densityless than 1 g/cm³ and an internal bond strength of at least 0.35 MPa.

131. The method according to any one of paragraphs 116 to 131, whereinthe one or more compounds comprising at least two hydrogen atoms thatare abstractable in the presence of hydroxyl radicals comprise lignin,tannins, a novolac resin, bis-phenol A, modified phenol formaldehyderesin, humic acid, or any mixture thereof.

132. The method according to any one of paragraphs 116 to 131, whereinthe amount of the one or more free radical precursors present when themixture is heated to at least 60° C. is at least 25% of the one or morefree radical precursors combined with the plurality of lignocellulosesubstrates and the one or more compounds comprising at least twohydrogen atoms that are abstractable in the presence of hydroxylradicals.

133. A composite product, comprising: an at least partially curedcomposition having a density less than 1 g/cm³ and an internal bondstrength of at least 0.35 MPa, wherein the composition, prior to curing,comprises a plurality of lignocellulose substrates, one or more freeradical precursors, and one or more compounds comprising at least twohydrogen atoms that are abstractable in the presence of hydroxylradicals.

134. The composite product according to paragraph 133, wherein theinternal bond strength of the composite product is at least 0.4 MPa.

135. The composite product according to paragraph 133, wherein theinternal bond strength of the composite product is at least 0.45 MPa.

136. The composite product according to paragraph 133, wherein theinternal bond strength of the composite product is at least 0.5 MPa.

137. The composite product according to any one of paragraphs 133 to136, wherein the composite product has an internal bond strength of atleast 0.4 MPa and a density of less than 0.9 g/cm³.

138. The composite product according to any one of paragraphs 133 to137, wherein the composite product has an internal bond strength of atleast 0.4 MPa and a density of less than 0.85 g/cm³.

139. The composite product according to any one of paragraphs 133 to138, wherein the composite product has an internal bond strength of atleast 0.4 MPa and a density of less than 0.8 g/cm³.

140. The composite product according to any one of paragraphs 133 to139, wherein the composite product has an internal bond strength of atleast 0.4 MPa and a density of less than 0.75 g/cm³.

141. The composite product according to any one of paragraphs 133 to140, wherein the composite product has an internal bond strength of atleast 0.5 MPa and a density of less than 0.9 g/cm³.

142. The composite product according to any one of paragraphs 133 to141, wherein the density of the composite product is less than about 0.9g/cm³.

143. The composite product according to any one of paragraphs 133 to142, wherein the density of the composite product is less than about0.85 g/cm³.

144. The composite product according to any one of paragraphs 133 to143, wherein the density of the composite product is less than about 0.8g/cm³.

145. The composite product according to any one of paragraphs 133 to144, wherein the density of the composite product is less than about0.75 g/cm³.

146. A method for making a composite product, comprising: combining aplurality of lignocellulose substrates and one or more free radicalprecursors to produce a mixture of the lignocellulose substrates and theone or more free radical precursors; maintaining the mixture at atemperature less than 60° C. for at least 10 minutes while retaining atleast 11 wt % of the one or more free radical precursors charged to themixture; and then heating the mixture comprising at least 11 wt % of theone or more free radical precursors charged to the mixture to atemperature of at least 60° C. to about 300° C. to produce a compositeproduct having a density less than 1 g/cm³ and an internal bond strengthof at least 0.35 MPa.

147. The method according to paragraph 146, wherein the mixture ismaintained at the temperature less than 60° C. for at least 20 minuteswhile retaining at least 25 wt % of the one or more free radicalprecursors charged to the mixture, and wherein the mixture comprising atleast 25 wt % of the one or more free radical precursors charged to themixture is heated to the temperature of at least 60° C. to about 300° C.to produce the composite product.

148. The method according to paragraph 146 or 147, wherein the mixtureis maintained at a temperature less than 60° C. for at least 30 minuteswhile retaining at least 11 wt % of the one or more free radicalprecursors charged to the mixture.

149. The method according to any one of paragraphs 146 to 148, whereinthe composite product is in the form of a panel having an averagethickness, and wherein the mixture is heated to the temperature of atleast 60° C. to about 300° C. for about 3 seconds to about 20 secondsper millimeter of the average thickness.

150. The method according to any one of paragraphs 146 to 149, wherein,prior to heating the mixture comprising at least 11 wt % of the one ormore free radical precursors charged to the mixture to the temperatureof at least 60° C. to about 300° C. to produce the composite product, anamount of energy generated from the mixture due to any exothermicreaction is less than 20 cal/g.

151. The method according to any one of paragraphs 146 to 150, whereinthe composite product has an internal bond strength of at least 0.5 MPaand a density of less than 0.9 g/cm³.

152. The method according to any one of paragraphs 146 to 152, whereinthe one or more free radical precursors comprise a mixture of one ormore oxidants and one or more catalysts.

153. The method according to any one of paragraphs 146 to 153, whereinthe one or more free radical precursors comprises a mixture of hydrogenperoxide and one or more iron containing catalysts.

154. The method according to paragraph 153, wherein an amount of the oneor more iron containing catalysts present in the mixture is from about0.05 wt % to about 5 wt %, based on a dry weight of the plurality oflignocellulose substrates.

155. The method according to any one of paragraphs 146 to 154, whereinthe one or more free radical precursors comprise one or more catalysts,and wherein the one or more catalysts comprise one or more metals in theform of a complex bound to one or more complexing agents.

156. The method according to paragraph 155, wherein the one or morecomplexing agents comprise cyanide (CN), sulfate (SO₄ ²),ethylenediaminetetraacetic acid (EDTA), ethylenediamine-N,N′-disuccinicacid (EDDS), ethyleneglycol bis(2-aminoethyl ter)-N,N,N′,N′-tetraaceticacid (EGTA), diethylenetriaminepentaacetic acid (DTPA),trans-1,2-diaminocyclohexane tetraacetic acid (CDTA), iminodisuccinate(IDS), nitrilotracetic acid (NTA), or any mixture thereof.

157. The method according to any one of paragraphs 146 to 156, whereinthe one or more free radical precursors comprise one or more catalystsand one or more oxidants, and wherein the one or more catalysts comprisepotassium ferricyanide, iron ethylenediaminetetraacetic acid, iron(S,S)-ethylenediamine-N,N′-disuccinic acid, iron diethylenetriaminepentaacetic acid, iron ethlyleneglycolbis(2-aminoethyleter)-N,N,N′,N′-tetraacetic acid, irontrans-1,2-diaminocyclohexanetetraacetic acid, or any mixture thereof.

158. The method according to any one of paragraphs 146 to 157, whereinthe one or more free radical precursors comprise hydrogen peroxide.

159. The method according to any one of paragraphs 146 to 158, furthercomprising combining one or more polyphenolic compounds with theplurality of lignocellulose substrates and the one or more free radicalprecursors to produce the mixture, wherein the one or more polyphenoliccompounds comprise lignin, tannins, a novolac resin, modified phenolformaldehyde resin, bis-phenol A, humic acids, or any mixture thereof.

160. A method for making a composite product, comprising: combining aplurality of lignocellulose substrates, one or more free radicalprecursors, and one or more compounds comprising at least two hydrogenatoms that are abstractable in the presence of hydroxyl radicals toproduce a mixture; and heating the mixture comprising at least 11 wt %of the one or more free radical precursors charged to the mixture to atemperature of at least 60° C. to about 300° C. to produce a compositeproduct.

161. The method according to paragraph 160, wherein the mixture ismaintained at a temperature less than 60° C. for at least 10 minutesprior to heating the mixture comprising at least 11 wt % of the one ormore free radical precursors charged to the mixture to the temperatureof at least 60° C. to about 300° C., and wherein the composite producthas a density less than 1 g/cm³ and an internal bond strength of atleast 0.35 MPa.

162. The method according to paragraph 160 or 161, wherein the one ormore compounds comprising at least two hydrogen atoms that areabstractable in the presence of hydroxyl radicals comprise lignin,tannins, a novolac resin, bis-phenol A, modified phenol formaldehyderesin, humic acid, or any mixture thereof.

163. The method according to any one of paragraphs 160 to 162, whereinthe mixture comprises at least 20 wt % of the one or more free radicalprecursors charged to the mixture when heated to the temperature of atleast 60° C. to about 300° C. to produce the composite product.

164. The method according to any one of paragraphs 160 to 163, whereinthe one or more free radical precursors comprise one or more catalystsand one or more oxidants, and wherein the one or more catalysts comprisepotassium ferricyanide, iron ethylenediaminetetraacetic acid, iron(S,S)-ethylenediamine-N,N′-disuccinic acid, iron diethylenetriaminepentaacetic acid, iron ethlyleneglycolbis(2-aminoethyleter)-N,N,N′,N′-tetraacetic acid, irontrans-1,2-diaminocyclohexanetetraacetic acid, or any mixture thereof.

Certain embodiments and features have been described using a set ofnumerical upper limits and a set of numerical lower limits. It should beappreciated that ranges including the combination of any two values,e.g., the combination of any lower value with any upper value, thecombination of any two lower values, and/or the combination of any twoupper values are contemplated unless otherwise indicated. Certain lowerlimits, upper limits and ranges appear in one or more claims below. Allnumerical values are “about” or “approximately” the indicated value, andtake into account experimental error and variations that would beexpected by a person having ordinary skill in the art.

Various terms have been defined above. To the extent a term used in aclaim is not defined above, it should be given the broadest definitionpersons in the pertinent art have given that term as reflected in atleast one printed publication or issued patent. Furthermore, allpatents, test procedures, and other documents cited in this applicationare fully incorporated by reference to the extent such disclosure is notinconsistent with this application and for all jurisdictions in whichsuch incorporation is permitted.

While the foregoing is directed to embodiments of the present invention,other and further embodiments of the invention may be devised withoutdeparting from the basic scope thereof, and the scope thereof isdetermined by the claims that follow.

What is claimed is:
 1. A method for making a composite product,comprising: combining a plurality of lignocellulose substrates and oneor more free radical precursors to produce a mixture of thelignocellulose substrates and the one or more free radical precursors;maintaining the mixture at a temperature less than 60° C. for at least10 minutes while retaining at least 11 wt % of the one or more freeradical precursors charged to the mixture; and then heating the mixturecomprising at least 11 wt % of the one or more free radical precursorscharged to the mixture to a temperature of at least 60° C. to about 300°C. to produce a composite product having a density less than 1 g/cm³ andan internal bond strength of at least 0.35 MPa.
 2. The method of claim1, wherein the mixture is maintained at the temperature less than 60° C.for at least 20 minutes while retaining at least 25 wt % of the one ormore free radical precursors charged to the mixture, and wherein themixture comprising at least 25 wt % of the one or more free radicalprecursors charged to the mixture is heated to the temperature of atleast 60° C. to about 300° C. to produce the composite product.
 3. Themethod of claim 1, wherein the mixture is maintained at the temperatureless than 60° C. for at least 30 minutes while retaining at least 11 wt% of the one or more free radical precursors charged to the mixture. 4.The method of claim 1, wherein the composite product is in the form of apanel having an average thickness, and wherein the mixture is heated tothe temperature of at least 60° C. to about 300° C. for about 3 secondsto about 20 seconds per millimeter of the average thickness.
 5. Themethod of claim 1, wherein, prior to heating the mixture comprising atleast 11 wt % of the one or more free radical precursors charged to themixture to the temperature of at least 60° C. to about 300° C. toproduce the composite product, an amount of energy generated from themixture due to any exothermic reaction is less than 20 cal/g.
 6. Themethod of claim 1, wherein the composite product has an internal bondstrength of at least 0.5 MPa and a density of less than 0.9 g/cm³. 7.The method of claim 1, wherein the one or more free radical precursorscomprise a mixture of one or more oxidants and one or more catalysts. 8.The method of claim 1, wherein the one or more free radical precursorscomprises a mixture of hydrogen peroxide and one or more iron containingcatalysts.
 9. The method of claim 8, wherein an amount of the one ormore iron containing catalysts present in the mixture is from about 0.05wt % to about 5 wt %, based on a dry weight of the plurality oflignocellulose substrates.
 10. The method of claim 1, wherein the one ormore free radical precursors comprise one or more catalysts, and whereinthe one or more catalysts comprise one or more metals in the form of acomplex bound to one or more complexing agents.
 11. The method of claim10, wherein the one or more complexing agents comprise cyanide (CN),sulfate (SO₄ ²⁻), ethylenediaminetetraacetic acid (EDTA),ethylenediamine-N,N′-disuccinic acid (EDDS), ethyleneglycolbis(2-aminoethyl ter)-N,N,N′,N′-tetraacetic acid (EGTA),diethylenetriaminepentaacetic acid (DTPA), trans-1,2-diaminocyclohexanetetraacetic acid (CDTA), iminodisuccinate (IDS), nitrilotracetic acid(NTA), or any mixture thereof.
 12. The method of claim 1, wherein theone or more free radical precursors comprise one or more catalysts andone or more oxidants, and wherein the one or more catalysts comprisepotassium ferricyanide, iron ethylenediaminetetraacetic acid, iron(S,S)-ethylenediamine-N,N′-disuccinic acid, iron diethylenetriaminepentaacetic acid, iron ethlyleneglycolbis(2-aminoethyleter)-N,N,N′,N′-tetraacetic acid, irontrans-1,2-diaminocyclohexanetetraacetic acid, or any mixture thereof.13. The method of claim 1, wherein the one or more free radicalprecursors comprise hydrogen peroxide.
 14. The method of claim 1,further comprising combining one or more polyphenolic compounds with theplurality of lignocellulose substrates and the one or more free radicalprecursors to produce the mixture, wherein the one or more polyphenoliccompounds comprise lignin, tannins, a novolac resin, modified phenolformaldehyde resin, bis-phenol A, humic acids, or any mixture thereof.15. A method for making a composite product, comprising: combining aplurality of lignocellulose substrates, one or more free radicalprecursors, and one or more compounds comprising at least two hydrogenatoms that are abstractable in the presence of hydroxyl radicals toproduce a mixture; and heating the mixture comprising at least 11 wt %of the one or more free radical precursors charged to the mixture to atemperature of at least 60° C. to about 300° C. to produce a compositeproduct.
 16. The method of claim 15, wherein the mixture is maintainedat a temperature less than 60° C. for at least 10 minutes prior toheating the mixture comprising at least 11 wt % of the one or more freeradical precursors charged to the mixture to the temperature of at least60° C. to about 300° C., and wherein the composite product has a densityless than 1 g/cm³ and an internal bond strength of at least 0.35 MPa.17. The method of claim 15, wherein the one or more compounds comprisingat least two hydrogen atoms that are abstractable in the presence ofhydroxyl radicals comprise lignin, tannins, a novolac resin, bis-phenolA, modified phenol formaldehyde resin, humic acid, or any mixturethereof.
 18. The method of claim 15, wherein the mixture comprises atleast 20 wt % of the one or more free radical precursors charged to themixture when heated to the temperature of at least 60° C. to about 300°C. to produce the composite product.
 19. The method of claim 15, whereinthe one or more free radical precursors comprise one or more catalystsand one or more oxidants, and wherein the one or more catalysts comprisepotassium ferricyanide, iron ethylenediaminetetraacetic acid, iron(S,S)-ethylenediamine-N,N′-disuccinic acid, iron diethylenetriaminepentaacetic acid, iron ethlyleneglycolbis(2-aminoethyleter)-N,N,N′,N′-tetraacetic acid, irontrans-1,2-diaminocyclohexanetetraacetic acid, or any mixture thereof.20. A composite product, comprising: an at least partially curedcomposition having a density less than 1 g/cm³ and an internal bondstrength of at least 0.35 MPa, wherein the composition, prior to curing,comprises a plurality of lignocellulose substrates, one or more freeradical precursors, and one or more compounds comprising at least twohydrogen atoms that are abstractable in the presence of hydroxylradicals.